It's good to treat your music collection as an archive - it's not unheard of that artists pull their albums from Bandcamp or other services, with no possibility for you to redownload it if you ever decide that the format you downloaded it in is no longer up for the task. And especially with commercial releases you will never know if buying the release again in some other place will give you the same experience - it might be a bad remaster and getting hold of the original version might be impossible legally.