Personally cant see the point! Theres not a lot of bolt to collect any metal.
You shouldnt be and chunks of metal in there. If there is then you have a problem.
I normal check my drained oil with a high powered magnet on a long bolt.
If your oil looks like someone has poored a tube of glitter in there, then again you have problems.
I wouldnt bother, but at the price then why not?