Not sure popularity necessarily suggests it's good, but possibly just what people have most heard of or is easiest to setup with. This is going to be even more true now that Claude subscriptions are going to be essentially vendor locked.

Given how far ahead OpenAI was in mindshare, monthly users, and revenue over Anthropic when Claude Code came out, I think we can conclude there's at least some substance behind claims of Claude Code's better product quality.

It definitely suggests it.