A lot of top competition shooters use airsoft to practice. There's even an airsoft based action shooting sport called (shockingly) Action Airgun
for people who are interested.
The great thing about airsoft is that when it's 10 degrees outside like it gets here in Indiana, you can still practice fundamental skills like drawing from the holster, getting your sight picture and breaking a shot. While you can certainly tell the difference between the trigger on an airsoft pistol and the trigger on say, a ParaUSA LTC; what is important is that you're building the muscle memory necessary to perform the act of drawing/sight picture/break the shot in a stress situation, whether it's an actual gunfight or an IPSC/IDPA match.
Plus, it's a lot cheaper than shooting real bullets. You can burn through 1000 rounds of airsoft with a CO2 powered gun for 5, maybe 10 bucks which isn't even something you can do with a .22 any more.