"Would something like these be good enough to use as food for Tilapia?"

Yes. In tilapia-prawn policulture one of the main advices given is to seed prawns first and a month later seed the tilapia fingerlings. Why? Because tilapia can eat the young prawn post-larvae. But I think that might be expensive. Might you think about using artemia salina instead (sea monkeys), this is cheaper!