She checks them every time she's on her computer, no point in closing them and they are always posting to social media every day, whereas you may get a generic email once a month if they even have a mailing list. Instagram is admittedly a LOT better at showing what you want than FB, as she follows them all there as well, but sometimes they post different stuff on each. She wants to both support and help these bands and band members by engaging on their socials so they actually get shown to more people. These are metal bands, so not big by any means, although some of them are still "large" or well known in their genres, but still struggle to get any good traction online. Most people in metal bands still have full time jobs, even if they are at the top of their genre (excluding the mega bands people have heard of).