IF size was effected and i could change into a large character to block off doors more effectively or to have better reach with weapons and maybe if squeezing was a thing or cover and you could hide easier behind stuff sure i would be all for it.

That sounds more like Enlarge/Reduce which is a more useful combat spell admittedly.
Disguise Self for me is for fun, different approaches to non-combat situations. And yes, there will be alternative ways of approaching those situations for other characters, but I like having many different options that fit with different characters I am roleplaying.