I don’t think that is necesarily true, depending on what other gear you have inline. A digital effects processor only manipulates a very small electrical output after all, well before any amplification occurs. I certainly wouldn’t recomend (jesus, I need a spell-checker) playing live without some other gear to reinforce it, but I do know folks who’ve gigged with very little more than a cheap digital effects processor and a loud amp.
"People want to know why…I write such gross stuff. I like to tell them I have the heart of a small boy — and I keep it in a jar on my desk." <-Stephen King