The benefit of DUG IN is very interesting for platoons in defense or immobile:
Thoses units are quite invulnerable against soft weapons like rifles, LMG, HMG, Light/medium mortars (FP 5 or more)
It's intersting for units with a save of 5+ like gun teams and all unarmoured units in defensive position. It's also interesting for Staff team who are vulnerable (and useless the first turn of game
).
Gone to Ground is also a very intersting option because it protect units that don't shoot and don't move. It's automatic and they become harder to touch. It's vrey intersting for veteran because at more than 40cm, they cn't be shoot at. However, they are still suitable target for bombardment.
So, all those advantages make difference between a veteran player (who will use and abuse) and a newbie (who will often forget it).