Just like winch tow, auto tow, landings on tow, spins, etc...
I think a self-launch endorsement is good training. Each is an eye-opener.
Without training in these elements there's an increased chance of misconception.
If a self-launch endorsement isn't available where you are, at least read Eric Greenwell's guide to self-launch sailplanes.
Yes, the FES is a different animal, but as far as I can tell there's no 100% guarantee.
Jim