Although I'm not wearing a belt yet, That's what I feel like pros of belts.
Depends on brands, but they do look nice. Some high end brands allow customers to choose color of lining and add personal engravings, so I feel that I can make belt look beautiful on me!
Max9 feel constantly protected and loved
I would feel protected from bottom dysphoria and I feel keyholding by loving and caring person would make bond in relationship stronger.
Max9 You don't need to decide what underwear to put on
Basically I can't get underwear in align with my gender identity without tucking, while chastity belt can do both, as a tucking tool and underwear!
Max9 You're always perfectly dressed
Exposure is not my thing, maybe due to lack of confidence now, but it's also my personality I guess. I believe I can look beautiful without too much exposures.
Jonas They enable another level of faithfulness and commitment to a [future] life-partner.
A reason why I am considering to keep wearing belt after marriage and post-op. (Of course I'll need completely new belt by then) I want to be committed to my life-partner who saved my life when I wanted to end it myself (due to dysphoria / dealing with family matters with my identity). However, it may depend on my partner's thoughts as she might think differently. Even if she may be okay with holding keys continuously at first time I will be belted, she may change her mind when I become post-op. If that happens, I won't be forcing her to hold keys if she doesn't want to do so anymore. I believe mutual agreement is important when it comes to wearing / keyholding chastity belt.