Also for immersion: Sturmpioneers were combat troops, while Engineers, Pioneers & Rear Echolons were not meant to engange in actual combat at the front line. Their role was to repair bridges, maintain logistics etc.
Interestingly enough, pioneer squads were one of the most trained and well equipped battalions of the war.
Pioneer squads were typically equipped with close combat weaponry, flamethrowers, grenades, hollow-charge explosives, and mines for destroying enemy positions. They also had dedicated flamethrower teams, MG teams, and AT weapon teams unlike most other armies that had to call on this support from separate units.