but, you can do vibrato and tremolo without using the LFO feature of the PCE. You can hear it in my Doom video, more towards the tail end though. I think I did it in R Type too and and Shadow of the Beast, actually.
I don't use LFO.
Also, it's called a whammy bar
No one really actually calls it a trem bar. Probably because it's wrong. Blame Fender. They sell their vibrato bridge assembly as a "tremolo", where other companies (Bigsby) sell it as a vibrato. As far as actual tremolo goes my Ampeg had a real nice tremolo built in. That with my Gretsch made some real nice rockabilly noise.
I tried to simulate a real fast tremolo in one of the Insanity chiptunes. I think it was used on the green-robot level.
Also, you don't mean to say LFO is useless in audio for music as a whole, right? Just for PCE?
Nat: Watch this if you want to see LFO in action
The best way to describe LFO without being technical is done with one simple word
DEVO.