You are right, if you fly a glider that has the performance to soar and the conditions allow it, but many flights will be short, especially during the beginning period. I know because my daughter is learning to fly gliders and her instructors do not give her a chance to do soaring, nor are they happy to allow her to solo. Usually there are people waiting their turn and they become disenchanted if they have to wait too long, letting my daughter know after she lands (she is 16 and an easy target).
We fly together using a C150 or C172 and the rate is not too bad. She has soloed both and is working toward her Private, but gliding is her real love.