I can speak to this a little bit. My dad was afraid for me or my brother to run a saw when we were growing up. We heated with wood, but he did the cutting and my brother and I did the splitting and stacking. When I started out with saws a few years ago, my hand filing was terrible. I understood the gist of it, but couldn’t keep my angles consistent. Part of the problem was that I would also rock a chain pretty regularly because I didn’t know where the tip of my bar was at all times. A rocked chain and a novice filer is a recipe for inconsistent chains. As I got better with a saw and kept my tip out of the dirt, my filing became better because the tooth angles from the factory gave me a guide to go by. I tried the husky guide and the cheap clamp file guides out, which also helped me learn the proper angles. I got a grinder earlier this year for my rocked chains, but prefer to hand file to touch up a sharp chain every couple of tanks. It all just really depends on how new someone is to running a saw. A lot of people don’t have someone to show them the ropes and have to learn from trial and error. I still use a flat clamp on file guide and take my time, but my chains cut really well.
These sites have really helped me with my filing. I don’t think it’s something most people pick up right away. Even if you get the top plate sharp, it won’t cut worth a damn with a dull or uncleaned gullet.