> What's the use case for Zai/GLM?

It's cheap :) It seems they stopped it now, but for the last 2 month you could buy the lite plan for a whole year for under 30 USD, while claude is ~19 USD per month. I bought 3 month for ~9 USD.

I use it for hobby projects. Casual coding with Open Code.

If price is not important Opus / Codex are just plain better.