I have a 20 year old computerized machine and have always heard not to use those magnetic mats that lay on the base of the machine. I have 2 of the magnetic pin grabbers that I use on my sewing table. One sits right behind the machine, where my quilt pieces run through....so that as I sew, I pull the pin and toss it at the grabber. It work great. Then, on the front of my table about 1 1/2 inch from the front of my machine, I glued a stip of magnetic tape to catch the pins I am wanting to keep handy, keeping them from rolling off on the floor.
With a 20 year record, I would say it is safe to have them nearby but probably NOT directly on the machine itself.
This is from my own personal experience.
June