I use old PC and Mac because it continues to work. I also have an old Macbook (2008) that I wish I could repair, so I could continue using it. While the old macbook doesn't run modern software, it ran Linux well, and it would've been fine running Home Assistant, web servers, NAS with Thunderbolt2/3, etc. I'd hate seeing old computers go to e-waste, if I could just fix it cheaply. Also, I might've run some classic software that is no longer supported on modern system, like old Adobe Photoshop that ran without subscription, and classic games as well.