Yes, turning takeoffs are pretty common in confined area ops in seaplanes. Often, departing with a load is the only time you need to do a turning takeoff.
It was interesting in that video that the only landing they show he was circling to a landing, and at touchdown, he was drifting sideways. I'm betting someone got a good neck snap out of that touchdown. Not recommended. And, in a Pacer, of all airplanes, a circling arrival will take more lake than just landing straight ahead....

Those things sink like a stone, especially on floats.
Turning takeoffs work pretty well until there's a bit of wind......then things can get sketchy, depending on the velocity and direction of the wind. Turning on the water into a wind can be a career limiting program with sufficient breeze.
But, one of the nice things about float flying is that often you can use the "runway" twice.....once in one direction, then again on the way back for takeoff. Especially when heavy.
MTV