Tape is very handy allright, I usually get the engineer to burn down a dvd of all of the wav files at 44Khz @ 32bit float to import into other applications BUT the problem is the time it takes to burn each track down. This can take up to an hour and a half alone because each file is in the region of +50MB and in any given track including drums, layered guitars etc you could end up with 35 track in no time.
Kevin made a very valid point about set up times to. Mic'ing a cab/amp takes a minimum of an hour if you are lucky. The more professional a recording you are going for the longer it takes. Metallica for example would spend about a month getting their guitar tones together.
Basically, it's not as easy as going into the studio, pluggin up and hitting record - although I've tried that before too!
Re caffeine, I actually shred faster and can pull off more extreme improv when I'm loaded on a few mugs of strong black coffee. Everyones different I suppose...