If you fly in BE on international you will probably get into either BE lounges or Sky Clubs depending on which airport you are in. With the AMEX Reserve Delta credit card you can get into all domestic SCs and only a couple international ones. If you are a full member of Sky Club you can get into any Sky Club even without a ticket on Delta. Here is the list (use the pulldown menu to choose type of access e.g. SC member, pass holder, credit card etc).

https://www.delta.com/traveling_chec...ions/index.jsp

Even being a Sky Club member won't help in the airports that aren't listed in that link above. If you don't fly domestic much at all, lounge access will be limited to only those airports have Sky Clubs. Sadly, you won't get into Air France or KLM clubs with a SC card.

If you only fly 1 or 2 times a year, then you are better off paying for each entrance to the clubs if you can, because membership is expensive. However if you do have need for the Amex card, then you can use the Delta Reserve Amex card to get into the domestic clubs.

The Delta Reserve Amex Card will also get you up to 30,000 MQMs per year - 15,000 when you spend $30,000 and 15,000 when you spend $60,000. That is a lot of spending, I know. It is especially hard to do because they don't give out decent credit limits on that card. The card itself costs $450 a year, so really you are paying for club access with a card membership fee - but again not all clubs, only those listed on the link.