Please see the full blog post here: https://blog.sia.tech/choosing-asics-for-sia-b318505b5b51
There are essentially a few main reasons:
- GPU mining leaves smaller cryptocurrencies more vulnerable to attack.
- ASICs better align incentives between users and miners, because they introduce a switching cost for miners.
- Someone at some point will develop ASICs for Sia. By introducing them first, and selling them to our users, we can ensure that the network remains decentralized.