writes:

A take off is a take off.

So why is someone with only a license to fly an airplane not allowed to take
off in a helicopter?

So by your logic if the engine at the end of the rope quites, there is
no problem because it isn't directly bolted to the glider?

There is no engine at the end of the rope; there's another aircraft at the end
of the rope.

The recovery technique for a glider is different from that for a powered
airplane. It's as simple as that. For powered airplanes, trying to turn around
and go back to the airport after a total power loss on takeoff is a really,
really bad idea.