Sometimes, me and other players (that i have seen) want to move to another location to build a new base and forget the old base
When we dismantle a piece, we receive a few materials back, but if we dismantle the bottom wall of a taller one with 3 or more walls stacked, we will receive only the few materials of that first wall. The walls stacked above will be lost.
So, besides its a huge time taker to dismantle each piece of a old base, there is no motive to demolish a entire old base and remove that weight on server.
There is a demolish option when a base decayed. Why we cant have this same button on our own buildings??