If you notice, I released an update to this mod to make it work with spidertron within a day of the release of 1.0.
Unfortunately, if you started a game before then, you won't have that change since this mod is mostly a scenario, and scenarios get stored in the savegame file. :-/
Even before this change tanks and cars already worked. The game has exceptions for certain things. It allows wires, modules, artillery remotes, tanks, and equipment grid items (for loading into vehicle equipment grids) in your inventory. It also possibly allows a smattering of other things. I'd have to look at the code for the complete list.
The reasons it allows this is because (as you pointed out) there is no way to have robots place these things easily. Modules, and wires, sort of, if they're already part of a blueprint. But not if they weren't, which made creating a new blueprint with wires and modules impossible.
And I added the spidertron remote and spidertron to this list.
Unfortunately, spidertron cannot be loaded with inserter arms. So there isn't really a way to manipulate spidertron's inventory or load it with rockets. But you can load up its equipment grid, and so with lasers it can still take on an attack role. But not being able to load its inventory means you can't really have it be a remote base builder.
So, the short answer is that if you started a game very recently with the newest version of BNW, spidertron will work fine for you, mostly.
