This is an interesting topic and discussion.
While actuated whatever blocks, combined with player above sensors, or rather even just simple pressure plates that only react to the player... sure, they're great alternatives for doors from practical point, BUT
they are post skeletron, so, late pre-hardmode, meaning you would either have to consider them from the start, or really redesign your buildings once the materials are available (except if cheated in via cheat sheets or other ways)
but that's just the practical side of things. from builders' viewpoint, it would be awesome to have some doors/gates that are larger than the usual.
The is the large gate, but it's just one design, and won't fit everything, not to mention, technically and practically speaking, it's one of the "weakest" doors due to it opening upwards, not to the side, making it impossible to block from the inside in the simple way most doors you can make zombie-proof with (just place anything, like any furniture right next to it)
so, larger doors/gates could fit to some builds, whether it's a castle, dungeon, city severs, prison, etc.
while still keeping that behavior (opening to the sides) what makes most doors relatively safe. (that behavior also can add to the looks too, so you can see these large gates open)
practically speaking, actuators might make better doors. (but that's part because town NPCs sometimes behave dumb and open the doors to let in enemies)
but building design-wise, large gates that open to the sides could be quite useful in all sorts of builds. that is what I think.