The difference from the little I know is about weight. A metal cage adds so e weight and that pulls on the testicle behind which the anchoring ring is locked.
This can get very uncomfortable or even painful, so cage wearers usually prefer underwear that supports the weight of the cage.
For belts regarding underwear there is not much difference between men and women - whatever floats your boat and hides the belt well enough.

    Mike_Orca On the contrary, no more need for male underware with my belt because there is no more bulge in the crotch.

    so you don't wear any extra underwear since you switched from the cage to the belt?

        Angelina
        I still wear panties but mostly plain panties basically designed for women a they fit better over the belt.

            Mike_Orca I still wear panties but mostly plain panties basically designed for women a they fit better over the belt.

            everyone as they like, my father has not worn extra underpants over the belt since he started wearing it.

            • Kaja replied to this.

                Kaja

                no, why? when i'm at home, i don't wear extra underpants under my belt either.

                  a month later

                  Pantyhose or tights hide them well.

                  • Ines replied to this.
                    25 days later

                    My Neosteel Fun creates a fairly flat profile in front, so my typical men's briefs end up being a little baggy in that area. I find that some support is nice for the testicles since there is no shield on the Fun, I did some searching and found some women's briefs that provide good support, do not look feminine in any particular way and they are comfortable. I didn't want something feminine and I knew I was unlikely to find something that fits closer in that area in a men's variety, so these worked out pretty well.
                    https://www.amazon.com/dp/B0BBLN7B8S/