I’ve used a phone on the bars for a while, I’ve got a nice big bar bag for the commuter with a transparrent map pocket (Which the phone’s touch screen works through) which works quite nicely but is quite bulky…
I’ve used one of those zip up bar mount phone holders in the past too but it wasn’t that robust for £20 and died after about 10 months use…
On my “Proper” road bike I’m now keen to de-clutter the bars and my current phone is even bigger than the my previous so it’s just been going in the back pocket (battery life is much improved by not using the sccreen), I think I’d like to see some basic information on the bars but I’m not arsed about anything fancy, just an indication of Current/Avg speeds would do me TBH so I’m thinking about buying a cheap computer to leave on there permanently.
If I want to log all the other stuff HR/cadence/etc I could just but Ant+/BT sensors and use those with the phone, but too much data on the bars is a bit of a distraction IMO, log it and pour over the data when you get home…
The other option is a GPS running/multisports watch whihc you can then use for other stuff, but then like you say, you already own a GPS device in the form of a phone, so paying for another does feel a little silly when you’re not quite a “serious athlete”… Hey ho…