Glass carriers are a royal pain in the butt. There are issues with Newton's rings and dust (4 extras surfaces to collect it). Glassles, on the other hand, eliminates the Newton's ring problem and there is less of a dust issue as only the negative can collect it.
Glassless carriers also eliminate another attribute of glass carriers; negative flatness. Hence, way back when, when I still did wet darkroom work, I printed most images with a glass carrier (Beseler 45 with 4x5 glass carrier). All the medium format, Polaroid 665 PN negs, and 4x5 sheet film negs were printed with a glass carrier. 35mm was a mix. For most, I used a glassless carrier, but occasionally I used the 4x5 glass carrier. When I needed to print the the very edge of an image whose edge was extremely close to the end of the strip the glassless carrier offered two choices; crop slightly or loose support for the end of the neg and loss some sharpness since the neg wouldn't be as flat. The glass carrier was the cure.
"You pays your money and makes your choice", as the saying goes. For me it was a glass carrier.