Water proof and supposedly easier to see/read in direct sunlight. Mounts are not the typical "car" mounts. They have mounts dedicated to handlebars, etc. Power supply is usually different as well instead of the typical 12V plug.
It is as you've said.
Just read the reviews on this unit ..... they are good!
I always took along my car unit in a zip-loc and it did the trick but is a hassle not being mounted properly and the battery doesn't last at all.
5 hours battery life on the "rider" even with a way brighter screen. The base comes with the hardware to hard wire it in permanent if you like and that is what I will do. Glove friendly and will route you on the winding roads if you prefer.
Under "Find" points of interest, it had find "DDT"

Heck I can't go wrong with that feature!

The gloves are more what I'm thrilled about!
Spring and fall riding in the mountains up here can be cool even down right cold, so for me they are a good investment for sure.

$225.00 US was well worth it to me to save screwing around with the car one or my phone