Is cartridge Demagnetizing Necessary?

Benn awhile since I posted.  Hope you all are well during this crazy time.
Have a question.  Is cartridge demagnetizing necessary and/or does it actually yield sonic results.?  Also. I read that by playing a record and at the same time shorting the RCA tonearm cable plugs together will be just as effective as using an actual demagnetizer.  Is this true?
Thanks all for your responses.