Terrible advice!
Another one who can't set a controller up!
Nope, it's not terrible advice; if it were, so many wouldn't be doing it. Fast flow means you work faster, which isn't a problem if you're confident in your ability.
If you're not confident you'll waste a lot of water and not be as quick.
So If I advise someone to quit smoking, that would be terrible advice- as so many do it??
No, still terrible advice. I can work as fast as anyone with an "optimum" flow. Been using a controller for about 6 years without issue, I also understand how to set it up, how it works & what it's designed to do.
Full flow means mega splash back, wasted water, more battery power consumption etc etc- basically, just completely unnecessary!