I've never raced and somehow think I never will but I've got a newish tourer with bar-end shifters and, though it arrived perfectly indexed, when the cables stretched a little, I thought I'd try using them as friction shifters for a couple of miles. About 3,700 miles later, I still haven't got round to retuning it. A clean shift is my good shift, a clunky slippy chain is my bad shift, and, no, changing gear standing is difficult enough indexed or not. If the flappy paddles on my SRAM bike gave me the option to use it like a friction shifter on the lighter bike, I'd choose it.
Mind, I grew up on bikes before indexing was even a glint in its chainring's eye.