Good advice and i'm always careful with the tools i'm given unless i get an idea how to modify them slightly so they function longer or better or both.
I would also take that ad with a grain of salt. The bump to feed plastic lines came about because people got tired of the hassle to take the old metal cutting disc or blade out and resharpening it. You needed a bunch of tools or had to pay someone to do it. The bump to feed plastic line did away with that.
The bump to feed thing I hate because it's sitting on the hub that's spinning at a horrendous speed and will gets damaged with all the pebbles and crap a user inadvertently flings into the hub. The springs and gears holding the coil of plastic line will just wear down from the constant abuse. Even if you are super careful.
I got a gas powered one with a hub that just holds a length of cable. Sure I could buy those expensive pre-cut ones... or I could use a cheap line of plastic and cut my own. Brought 2000 yards of plastic line for $10 and probably only used a third of it in fifteen years. I kinda of regret buying that much now. Other than routine maintenance on the engine, it's been working swell for me.
Whatever blade you use is going to break. It's wearing down because it's hitting stuff that ain't just soft grass. You are also not really cutting stuff. You are bashing them with a high speed bat. That's why you can use zip ties to do this work. Just have it angled slightly so the stuff you are hitting doesn't come back at your tool.