@luis223344 What’s nice about my setup is I have the exact mono counterpart to my stereo cartridge (Lyra Atlas: SL + Mono), both on identical tonearms on the same turntable. Both also run through the same phono-stage.
I’ve been able to really see what a true mono cartridge brings to the table, i.e. comparing Atlas SL with mono button engaged vs the Atlas Mono. Some mono records almost sound stereo with the depth of soundstage the mono cartridge adds, and they play so quiet since the mono cartridge ignores the noise of the vertical grooves.
I think it’s worth it if you have a collection of mono records you play often enough.