To learn, the net needs to work.
It can not learn by just observing (well not usually)

It needs to act (produce an output), and a "teacher" needs to adapt
its properties (weights, thresholds etc) according to the errors the net made
regarding the optimal output.
If a net is trained, it can be used to work on new data, and not learn anymore.

So a bot yould either use an already trained net, that does not change,
or even learn ingame furthermore.