Why hasn't shopping directly inside ChatGPT caught on?

OpenAI keeps adding real shopping features (product search, live prices, instant checkout with some merchants), but I don't personally know a single person who buys through ChatGPT instead of just going to Amazon or Google.

Is anyone here actually doing their shopping this way? If so, what works well enough that you kept doing it? And if not, what's the real reason you haven't switched: habit, trust, selection, something else?