I'm assuming you're talking about
Bloodstained Mire and
Wooded Foothills. I run them for deck thinning purposes. Also, they're not limited to basic lands. If you look at the type line on
Sacred Foundry and
Stomping Ground, You'll see that they're labeled as "
Mountain Plains" and "
Mountain Forest", respectively. This means that, because
Bloodstained Mire and
Wooded Foothills can search up Mountains, I can search up either a
Sacred Foundry or a
Stomping Ground with them. In terms of
Eidolon of the Great Revel, it shuts down most other decks (apart from Iron). Yes, it damages me, but this is Burn, which is all about dealing as much damage to face as quickly as possible. Every card in my deck triggers it, but I'm likely ahead on life, so the damage to me will be less significant than the damage to them.