There would be no challenge for many helo pilots on this forum in jumping in a glider for the first time.
Well ... not so fast there. I'd suggest that an aero tow might challenge a helo pilot a bit, and remember that every landing in a glider is an EOL. However, as with helos, these things are meant to be operated by humans, so almost anyone can learn to do it. I am wondering what took our boy so long to learn to hover - I taught myself in 2 minutes!