Just like a child when he first learns to read.
The problem with realizing boundless knowledge is that real soon the boundaries become visible. Make a few bad calls and you will blame the tool if you understand. If not you won't realize that there really is test procedures.
And how will you deal with the rest of the car. I use a scanner about 30% of the time for engine management issues. The other 70% won't be accessible.
With that said I use OBDII scanners all the time, for quick specific reasons. Never for diagnosis. It would be like tieing both hands behind my back.
Bosch Master, ASE Master, L1
33 years MB technician