It depends how you forward images. I assume they are referring to how many/most services (like whatsapp/discord/telegram etc) don't just send the original file, but do some compression to save data. Do this a bunch of times and you end up with a photo that starts to show noticeable artifacts/pixellation.
I can't live without the EurKey layout! Even had to get approval to add it to our systems at one megacorp I worked for.