Yes it certainly is. I have Syntace C2 clip-on aerobars on my road bike. On long even descents being on the aerobars is slightly faster than being in a deep tuck with my chin on my stem. On cold days or in the rain, aerobars are also far warmer. Also more comfortable and save upper body strength. Bridging gaps on aerobars is a real eye-opener.

Of course you can't use them when you're closer than say 15' to a rider in front of you, but they're pretty useless then anyway because you're in the draft. My practice is to pull for long periods or ride solo on them. I ride hoods in a paceline, except 2nd and 3rd wheel I ride the drops. Doncha just love it when guys pull on the hoods? Kills me. Rolling pacelines, no aerobars, mostly in the drops.

Our tandem is fitted for aerobars in both captain and stoker positions. I can ride hoods in a paceline while Stoker rides her aerobars.