I started doing this on my first oil change - brand new engine (80 miles at first oil change). When I pulled the factory filter, I notices sparkly flecks in the paper folds. That's when I got the idea to slap a magnet onto the filter. I've done 2 more oil changes since putting the magnet on the filter. No more flecks in the paper - they're caught before they get to it. When I change the oil, I just wipe off any metal stuck to the magnet and stick it back onto the new filter. This way I STILL get an indication of the amount of metal pumping through the system, AND it stops it before it cycles through a second time... (and, it's free).

Think about it:
I can't imagine the drain plug magnets do anything at all, except for catching a few suspended particles when the bike is PARKED. With the engine running, only a tiny fraction of the oil will be passing anywhere near the oil plug. The engine would have to be stopped for anything to settle close enough to the drain plug for the magnet to attract the particles, and even then, any particles beyond the field of the magnet will remain in the oil.

If your oil pump was damaged by metal particles as you say it was, then your oil filter was NOT doing its job! I'm guessing it was probably a K&N or some other non-paper (i.e. metal mesh "reusable") oil filter.