That is correct for the majority of divers the exceptions being the minority of us that dive more frequently locally. Another reason may be that you want higher capacity tanks for longer dives. Very few dive shops rent tanks larger than 80 cf. Tank capacities of up to 130 cf. are available should you need or want them. Then there is the question of Nitrox fills and rentals of those tanks can cost more for a fill and may or may not be available for rental.
As an instructor I use higher capacity tanks to insure I have a backup capacity should an emergency arise with a student. I also have learned that the weight and buoyancy characteristics of different tanks can alter the amount of additional weight I may need. Not all tanks are the same.