A thing? It's a huge thing, and has been a huge thing for a long time.
Not internet lore. It's backed up by a LOT of science from some very reputable sources.
How good are they? People have switched from toilet paper filters to centrifuges and gotten better used oil lab results from the toilet paper.
Toilet paper filters absorb moisture, remove contamination at a VERY fine level, and even remove soot from the oil, which is ridiculously difficult.
A fresh diesel oil change turns black from soot within seconds of starting the engine. I see diesel engines running TP filters that have perfectly clear oil from beginning to end of oil use.
Considering that you can by these "filter cartridges" for pennies, it's quite incredible.