Mike here is one of my auto scrubbers on tile with some Judson Juice
I have stripping brushes on it similar to a stripping brush on a rotary
if the grout lines are larger then it will work if the head on the auto scrubber has hydraulic pressure, if the scrubber head applies pressure by the weight of the head then it probably won't work
the vacuum system also has to be powerful enough, if the scrubber is only a 2 battery machine then it probably doesn't have enough power, it won't have enough lift to get the majority of water out of the grout lines
if you use only the pads then the grout lines will eventually get dirty, the pads won't touch the grout lines