Note that gliders were also death traps, as were planes like the Storch, but no one stopped using them just because of it. They were used because they could carry troops into places planes couldn't, relatively fast. And landing a glider was a nightmare. Think of the Pegasus bridge assault for example: a miraculous landing, in the right place, at night. Or the landing to recover Mussolini. Now imagine they didn't need a proper landing area, with a long clear space.
Even if a WWII model could only carry 3-4 troops, it would still make a diference. Sniper teams, demolition squads, AT teams, small rifle squads, all could be lifted and dropped of at will. For special assaults, hunting partisans, scouting... look at what the tiny Bell H-13 did on Korea. So, assuming Germany could have a decent heli, say, mid 1943, that would make a diference. A cross-channel raid, at night, for sabotage, would be perfectly feasible; 5-6 helis, each carrying 4-5 men with demolition gear, flying at wave-to height... the radars of the time would either not pick them up or assume they were ships.