I do believe that if you have the magnetic one just close to the machine it'll mess up the computer system. Anything with a computer system in it needs to stay far, far away from a magnet.
What we've done is make one block of anyone's choice. Pinwheel, 9 patch, log cabin, whatever; fill it with polyfil or spare batting, and put a backing on it. Stuff it full enough and you have a lovely little "pillow" for pins. I have them all over the place. One by the machine, one at the cutting board, and one that floats with me to put pins in and take out when I need them. I just love the little things!