You have to ask the users who use SCAT (probably SECATT since SCAT got replaced by it) instead of LSMW to know the exact reason.
Both can be used to load data by recording method. While SECATT's main purpose is to simulate business processes, hence the recording, LSMW supports other import options, which are often ignored, probably for the same reason like others use SCAT instead of LSWM:
It is just convenient to use a tool that you know instead of learning something new.
For quick and simple fix or loading some test data in trainings the recording method is fine. If you have bigger migration projects then you are quickly at the end with static recording, no matter if is executed via SCAT or LSMW.