I can be pretty fussy, and obsess about chain details. Some guys 'just hit the cutters with a file' and cut lots of wood. Other guys just make a dull chain worse.
So, if someone finds something that works for them, I say, 'go for it'. I don't sell any of the file guides. or jigs, or grinders. I don't care if they pay someone to sharpen their chains. I am not offended if they do it differently than me. My only personal interest is if they are using a chain once, then throwing it away - then I want first 'dibs' on picking through their trash!
Every method of sharpening has its advantages and limitations. Each of the file guides have them, as well as free-hand filing. But so does new chain out-of-the-box for some guys!
Philbert