Yes the recent paper [1] that confirmed they were circular mentioned the similarities to plasmids in bacteria too!

In the nematode world, we create extrachromosomal arrays of transgenes by injecting plasmids into the worm’s gonad that then get passed down to progeny; the expression we see is almost always variable and mosaic and not every cell ends up showing it.

I would guess this technique used for decades in the field is actually an induced version of these!

[1] https://www.nature.com/articles/s41586-019-1763-5

One of the articles posted suggests that weeds use DNA circles to quickly adapt to herbicides.