Yep, that's correct. There are a lot of things that biologists tend to believe are out there, but are waiting for examples, which makes these kinds of discoveries very pleasant surprises.

For example, it could kinda be assumed that we would find a phage that contained a CRISPR, and that turned out to be correct (it uses it to target other phages that infect the same host cell).

Another fun example is a reverse-transcription based replicating plasmid found in a fungal mitochondria. Theoretically it was possible, but that madlad did it.

A phage that I assume exists is one that replicates via reverse-transcription, but that hasn't been found yet. I hope they find it soon!