[I've gotta be honest... although I appreciate anyone who does work for this community and I think that censoring adult roms out is a worthy cause, this utility never has had any legitimate purpose unless the fe you are using is "old and busted".
It may not be useful to you, but it is definitely useful to me and anyone else who has kids that may get curious and snoop around the Mame directories. FE filtering doesn't help this at all. There may be ways to lock down your computer so you can't get out of the FE, but this would require a lot of work (and if your kid knows more about computers than you, it may be impossible

). MCM is quick and easy to use, so it's still a win.
I use Mamewah and I find it simpler to delete the roms once with MCM instead of manually deselecting them each time I create a new filtered category.
Lastly it's true that updating Mame may be more difficult, but many people rarely, if ever, update Mame. I personally don't plan on updating Mame for many years. This is an acceptable trade off for me.