Technically( I really dislike that word but it applies here) yes, Gringotts is a roller coaster but practically I associate it just like you do….an attraction like Dinosaur/Test Track/Radiator Racers where it deserves a different category.
To me a rollercoaster requires track whereby a cart freely rolls on it. The free rolling feature must dominate the ride. Test track and the like feel entirely controlled with no free rolling features. Gringotts does roll but the whole experience feels just as controlled as Test Track to me.