It depends on the route you want to take. In the UK it won't help you, as you need 200 hours to get a CPL. In the US however, you can get a CPL (A) with 100 hours airplane time and the rest in gliders. If you're planning to do a year the the US as a flight instructor to build time, gliding will make that easier, if you're thinking of going straight into an airline I wouldn't bother. Stick and rudder skills will definitely make you a better pilot.