I have ghost shrimp both in my 5G hex with my male betta and in my 10G with a bunch of female betta. Sure, they get munched on every now and then, the ones that don't do a great job at basic janitorial work: picking up the food bits that I miss. I guess that's why they're like 30c at PetSmart, they're essentially feeders. When all of the ones I have now are eaten and gone, I'll just go get some more.
All of mine have the same name by the way: Snackfood.