I don't do mileage runs but do appreciate the Elite Status (psychological and physical benefits). Let's look at my facts for 1999:
On my preferred carrier, Air Canada:
74 segments upgraded at time of reservation(no extra cost to me)
6 not upgraded (Dash 8 flights, no business cabin)
On Alliance carriers:
1 segment upgraded (no extra cost)
3 segments not upgraded
On carriers with whom I have no status:
6 segments not upgraded
You can see that upgrades drive my loyalty and I definitely appreciate it. I pay the same to travel Canada to France (on my preferred carrier -- about $800US) as I do to travel from France to Africa (on Air France) yet I get upgraded on Air Canada everytime and have yet to do so on Air France. Does the upgrade make my travelling life comfortable-ABSOLUTELY! . . . and the benefits don't stop there:
1. I get free worldwide lounge access on all carriers in my alliance (Star) when flying a Star carrier plus I get anytime access to Air Canada lounges (even when not flying--yes it has come in handy on numerous occasions). Also get to use Air Canada arrivals lounges when flying AC internationally regardless of fare paid.
2. priority check-in counters which speed things up most of the time
3. priority waitlist/priority standby-has come in handy on several occasions, when others were left at the gate
4. 2 extra pieces on Air Canada and 1 extra piece of luggage on all Alliance airlines (not something I would generally use but nice to have for those rare occasions)
5. have gotten other specials not available to general members--contests, extra mileage promotions, four 3 day free weekend car rentals etc etc.
6. free companion anywhere, any fare awards (i.e. buy one get one free)
7. gifts at higher thresholds
8. awards transferable to anyone
9. seasonal reward sales
10. guaranteed seat even when oversold if booked 6 hrs in advance in full fare
11. lounge passes to give to friends/family when they are not travelling with me
12. concierge service (don't use)
13. and the last BIG ONE: no capacity controls on reward travel on Air Canada--if a seat remains unsold at time of reward booking, they must free it up for my reward travel even if reward inventory is sold out.
Am I happy -- most of the time. Would I do a mileage run--only if I was short by a small amount or I knew I was really going to need it the next year (even more flying).
Would I recommend mileage runs--I say go for it as long as it doesn't affect your family, your financial well-being and that you have some fun at your destination at least!