You can customize the steam controller config to set a button to Turbo, allowing it to automatically press "Kontinue" when you are AI grinding towers. This is just like some people are already doing with fight stick set-ups.

For example, the default gamepad config has the lower left bumper as "A," so I set it to Turbo when held down, and then set it to Toggle on. So I hit the left bumper once to begin the first fight of a tower and then it'll just continue through the tower till the end.

Actually I guess you could do this with any controller on steam, just be sure to change the config. But the Steam Controller has those extra bumpers which makes it easier.

Hope this helps!