I owned every generation of it and so did many of my colleagues. Can't recall it being regarded a curiosity. More like, serious business machine.
The main benefit was a nice(ish) keyboard for texts and emails.
I once wrote and emailed in a consultancy report from the back garden of a pub, just to prove I could. But it's not something I'd have been happy doing regularly.
If Psion had somehow added mobile data to their Organisers they'd have killed this market.
https://en.wikipedia.org/wiki/Psion_Series_5
The main thing these devices did was normalise ARM and pocketable form factors for serious mobile use. But they were really micro laptops and not large mobiles.
They were more like very early versions of the MacBook or Air. The iPhone - rightly - went in a different direction.
The platform was really limited, app development was tricky, but at the end it did the job and there were very few alternatives.
We actually ended up using emails as our sync mechanism: internet connectivity in places we served were as limited as you can imagine and also because of device limitation. It worked in a way that changes in data were serialized and sent to server that merged the data into the master and sent you changes back via email as well.