KQ321

NB: I've used links to the English version of the DB site where possible, but where English pages don't exist, I've linked to the German (Google Translate is your friend )

What kind of BahnCard (ie: 25 or 50, 2nd or 1st class) are you planning to get? The 2nd class BahnCard25 costs €62, so if you're going to spend more than about €250/year on DB tickets, it will pay for itself. Note that the BahnCard25 gets discounts on SparPreis and EuropaSpezial tickets, but the BahnCard50 does not. So, if you're going to travel primarily on these fares, you may find the BahnCard25 is a better option than the BahnCard50. If you're going to travel primarily on normalpreis fares within Germany, then the BahnCard50 is better (if your overall spend is high enough). Note that neither card gets discounts on Länder-Tickets or similar.

I'm not quite sure what you mean. You can use the BahnCard for as many tickets for yourself as you want. However, the discount is not transferable - so you can't get discounts off tickets for other people (although you can get a partner BahnCard for a spouse or similar, for a discounted price). When you present a BahnCard-discounted ticket to a conductor when travelling, you are supposed to show the BahnCard as well, to demonstrate you are entitled to the discount.

I think you can choose who to credit the bahn.bonus points to (ie: unlike most/all airline FFPs, it doesn't have to be credited to the individual traveller).

No direct experience of this - but if you do a dummy booking for a 2nd class ticket with a 1st class BahnCard, it shows the discount (but not the other way round, for a 1st class ticket with a 2nd class BahnCard, of course...)

Are you referring to the post about the 'SchnupperBahnCard'? AFAIK, these are cards which are sent out 'at random'* to 2nd class BahnCard holders, allowing their 2nd class BahnCard to function as a 1st class one for a limited period of time - presumably in the hope of enticing the holder into traveling 1st class once, and then getting hooked on 1st class travel. I don't think you can choose when you get one - it (might) just get sent to you at some point.

For the discount, or for earning bahn.bonus points?
The regular BahnCard discount only applies to DB tickets. However, I think all BahnCards come with 'RailPlus', which gives a 25% discount on cross-border travel between any two (or more) of a number of European countries (but not including France or Spain...) Awareness of this discount among ticket sellers is sometimes somewhat limited, but I've used it successfully for a number of trips entirely outside of Germany.

For earning bahn.bonus, you only get points for tickets purchased from DB. (So, I think a Europa-Spezial ticket booked from DB for the TGV from, say, Munich to Paris would earn points - but a TGV ticket purchased from SNCF would not).

I think so, yes - but as I understand it, the separate bahn.bonus card is only for people who want to collect bahn.bonus points, but don't want a BahnCard (although I am really not sure how many people would travel enough for it to be worth collecting points - but not enough to benefit from a BahnCard - unless perhaps they travelled solely on Länder-Tickets...) So, if you get a BahnCard, you don't need bahn.bonus card (and if you did get one, you'd presumably have 2 separate collection accounts...)

Yes, €2,000/year spend gets you 'bahn.comfort' status. I think the main benefits are:
- Lounge access
- Access to bahn.comfort reserved seats on long-distance trains (ie: there are seats set aside for bahn.comfort holders who haven't made a specific reservation; although these seats are marked, it seems other pax often don't understand what it means, and sit in them anyway - but if your German is good enough, you can ask them to move...)
- Access to 1st ticket counters
- bahn.comfort customer service number (for tickets, reservations, etc)

Depends what you want to redeem them for. Some of the items have unlimited availability, while others are linked to the 'normal' yield management system, and so availability may be limited (labelled as 'nach Verfügbarkeit' on this page).

See DB's lounge page for a list of lounge locations and basic info. All lounges have comfortable seats, power-sockets, free wifi, and complementary soft drinks (tea, coffee, Coke, lemonade, etc) - but no food. Some lounges have special 1st class zones, which are only for 1st class ticket holders, and in which drinks and light snacks (eg: croissant for breakfast) are served at your seat. Watch the opening times - if you've got a very late train (eg: CityNightLine sleeper), the lounge may be closed before your train departs.

Thanks to RailTeam, a bahn.comfort status card will also get you into SNCF, Thalys, Eurostar, NS and ÖBB lounges, if you are travelling on an international ticket. (And I think also SBB lounges, although it's not explicitly mentioned on the RailTeam site).

* ie: presumably not actually randomly, but according to a precise but unpublished algorithm...