This is version 1.10 with no community beta 1.2 patch.
Too bad for WeGo/H2 Entertainment, I've already moved on to RVGL with the assets from my original CD from 1999.
Is it necessary for enjoyment to use RVGL, and can it be used with this GOG version?
I'd say so, yes.
It brings up to 12 players in online races and supports 4 player split-screen local races.
Plus all the fixes and features from 20 years of community patching and also supports a full integration of the the Dreamcast exclusive Rooftops track and 14 cars.
Yes, RVGL is just a patch. You need the original game data and music from a legit source like GOG or the original CD.
However, there's still plenty illicit sources, since the game has been in abandonware limbo for 20 years.
Find everything you need here: https://rvgl.org
(You'll find the Dreamcast data there as well, since I guess that one is pretty much not available anymore anywhere.)