While I clearly agree, what I've experienced in my career (including other non-G FAANG / MAGAM / whatever it's called now companies) is that one will get some help over chat to fix some issue, but think "this is such a small issue that will only happen once" or just get too busy with other stuff and neglect to properly write up documentation or put it in one's PKM effectively.

Having chat history and being able to type "chat:"Bob Joe" mitigation jitter identity server" or whatever search query to dredge up the single useful command that slipped through the PKM cracks is so useful.

I guess one is forced to be disciplined about it, but I wonder if Google knows whether this chat-curtailment policy is basically costing them millions in wasted dev time because they have to re-ask for help and bother people. However, in my current company (using Teams), I still get re-asked for help all the time and usually quote reply my prior message saying "please search for this before asking. I found it easily".

I agree. It's about as bad as relying on shell history (which I don't keep either).

If you do something to solve a problem, that should go into a ticket or into a note file or even into a paper notebook.

I'm older, maybe this is partly generational. I find chat to be almost uniformly annoying, and I use it very rarely. I sometimes go days without even launching my chat client. I prefer email which doesn't have the expectation of "drop what you're doing an pay attention to ME!!" that chat does.