more thorough testing of the same drivers, plus I think (but am not 100%) you don't get the GForce Experience app with the Studio drivers.
There will be zero difference in the renders between the two types of drivers, but the Studio Drivers could possibly be more stable. NVidia's drivers are very mature, and driver crashes are a rare experience, but a graphics shop won't risk a multi-hour render on the possibilty, hence the better tested and lagging Studio Drivers.
BTW, I also have a 3090 (water cooled) it is a beast, but I plan on upgrading to a 4090 when they are finally here.