I've had zero problems with craiglist response emails. I've purchased a variety of stuff over the years. Sold a few things too. The blind email technique is a protection mechanism so that the seller/poster aren't in direct contact with each other, they are linked up via/through craiglist, so you don't get each others' actual email addresses, making it a bit harder to find you if there is any kind of nefarious intent. Of course as with any purchase from a private party, common sense is required. If I'm going to someone's supposed home to pick something up, I never go alone. Preferably I'll request a meeting in a public location, but sometimes this isn't possible, like when I went to pick up a dining room set, or a 4 poster bed.
I do a lot of buying and selling through various public portals like craiglist, Marketplace, various local buy/sell/trade sites on facebook, my greater neighborhood website. Zero problems.