I have no issue with either answer given. That said, I think this question deserves an answer "from the street".
I got my glider add-on in the summer of 2016, started training for it in the summer of 2015. I belong to a 100+ member glider club in the United States, of which 85 percent have their glider certification/add-on, 20 percent are CFIs and quite a few have flown gliders for 40+ years. Due to the nature of our club, during my training I flew with 15+ different instructors. And, of course, given the "stand around and tell war stories" nature of glider operations, I've talked glider flying with most of my fellow club members. During all flights I have undertaken and observed, the primary goal was ALWAYS to "remain airborne by taking advantage of thermal currents." (though we don't call them "currents"). The exception, of course, is training flights, where the primary objective was learning to fly gliders.
All of this said, I have NEVER, not once, heard the aircraft we fly refered to as a "sailplane". On the contrary, the word we use to refer to what we fly is glider, exclusively.