The Siege Tower is a vehicle in Survival Beginnings.
The Siege Tower is a waste of resources to make unless you need to wipe out a full tribe, OR you have a Lumbermill. They require 6 Wood Hulls, which are made with 12 Tree Trunks, (2 for each Wood Hull) 6 Large Tree Trunks, (1 for each Wood Hull) or 12 planks. (2 for each Wood Hull)
The Siege Tower for land transportation is mostly useless, mainly because of its slow speed (Max Speed 7). The real use of the Siege Tower is mainly what it's name says, for sieges. It's height and mobility will allow it to reach to top of a stone wall, allowing raiders using the tower to trespass enemy walls and destroy the village defended by them. Though few villages will be fortificated by a whole wall, due to making a whole wall would cost lots of stone and time, in those few villages where a stone wall is present, a siege tower will be really useful.
Palisade walls can be crossed over, too.
Another use is to make the siege tower home, but it is mostly futile because it doesn't have space, OR planting room.
Another more weird and rare use is as a storage room. The items will likely fidget all over the tower, but it could work.