At my previous job they had been using Notes since the company was founded in the early 90’s, meaning they lived through it being Lotus Notes, then IBM Notes and now HCL Notes.
Everything was deeply entrenched - email, warehouse inventory, ERP system, all documentation made in the entire company… just everything.
And this is for a scandinavian company manufacturing high tech devices for telecom and aviation, among other things.
It was… an interesting nightmare, constantly got in the way of any sort of productivity. Definitely contributed to me leaving early
I didn’t use notes much, but it was a platform ahead of its time, that thanks to IBM’s… IBM-ness was ignored and allowed to rot.