Simple Mobile apps have been very popular among FOSS enthusiasts. I've personally been using the Gallery, Contacts and the Phone app since a few years now. It's a shame that it has come to this, will be on the lookout for their forks.
Even if it's removed from fdroid because they want to close source it, I assume my current installations of their apps would be unaffected - just become stale and obsolete over time since they won't get updates... But as they're offline anyway, not too concerned in the short term. Hopefully the company respects the privacy amd care of the open source community and won't take that away from us, though. One way to find out.