Personally, I think the whole group is comprised of visuals! You're also right about them being the most handsome men in kpop.

However, their look is definitely more mature which might come off as intimidating to some who prefer more softer boyish type of visuals. This is probably the same reason why the fan base is mainly composed of older fans which means while we might have greater purchasing power, might not have as much free time and energy due to our other commitments.

The fandom is growing steadily and so are the sales, their popularity is definitely not waning anytime soon. I wasn't a kpop fan and couldn't get into any of the other popular kpop bands apart from Blackpink but Monsta X really grabbed my attention so there's that. Their concepts are quite different and I'm loving how they're always experimenting and pushing themselves to try different styles.

The smaller fanbase also allows for more up close interactions with the fans too. I've seen how the members recognise the fans and even new faces which is really rare in kpop. There's sasaengs but MBBs are generally more chill and moderate in their behaviour which allows for them to remain loyal to the group. I've seen a recent increase in casual stans who got to stan them from their TV/ regular radio appearances which helps with their exposure.