Small Form Factor (SFF) / 2.5" disks seem to have become more popular than LFF disks now due to them being preferable over LFF disks in many scenarios (lower power consumption, higher density, etc). However, LFF disks still seem to feature in major vendor's offerings (take the recently released Gen9 series of HP servers as an example).
Looking at the pricing of the disks, in most of the lower (sub-500GB) capacities, there seems to be little price difference these days. That begs the question, why are they still popular enough for vendors to feel it's worth investing in supporting them in their latest products? Is it purely because the LFF form factor disks are available into higher capacities than SFF disks, or are there other reasons why they are still popular?
Underlying this is the fact I'm trying to understand what objective justification there is for spec'ing out a modern server with LFF cages/disks over SSF. What scenario/requirements might mean LFF would be the preferred choice? Would you only really do this if you needed large, multi-terabyte disks at a sensible cost, or are there other reasons?