Paradise Garage belongs with the '67 Dominator Buggy. Besides the storage, Rockstar describes a gun locker and a secured place to drop off stolen goods so they can be traded.
The Ultimate text says you can 'conveniently store' the '67 Dominator Buggy here, and that the garage 'features a weapon locker plus a secure place to deposit stolen goods to be fenced.'
Fencing matters in VI. Previews describe stolen goods going to fences, cars losing resale value when damaged, and money gating some story progress.