I think it's like what Dan said, a legacy thing.
My Brother HS3100 had no workoffsets, only G92.
Kinda pain at first, but once you learn how to make sure not to overwrite the coordinate in the wrong place, you're good.
The Brother HS50A has workoffsets and G92. The G92 works the same way as the older machines, but I don't use it in the program to set the coordinate.
This machine has a separate screen where you can pick up your location, set it and let the program use it.
This machine can also use workoffsets ( G54-59), but the way you have to set them is a bit retarded so I only use it when it's necessary.
The Makino has a shitton of workoffsets and I use those explicitly. BUT! It still has the G92 and it works AWESOME!!!
This may be a parameter thing, but unlike on other machines it is not a global work-shift, rather a work-set.
IOW, whichever workoffset is active, calling G92 X Y Z sets that coordinate system, and ONLY that coordinate system without affecting the others.
My suggestion: If your machine is capable of using workoffsets as normally expected on other machines ( mill, lathe etc ) then use it and forget about G92.