While that's true even today there really isn't a product that wraps that API that is as simple to use as any of the major chat applications.

I've used OpenUI and it's fine but it's incredibly fiddly to configure and web integration is almost nonexistent (this was as of a few months ago so maybe it's better today).

I find https://msty.ai to be significantly better than any of the major chat applications. It has a ton of qol improvements.

I find TypingMind outstanding.

Many businesses both cost you money and also show ads.