I *personally* sort of hate it, but I know many think it's the only way to go. I'm no night fishing expert, so I'm definitely not the best person to be commenting on it.
That said, because I can't resist injecting my two cents (
), I've got several reasons for not liking it. By and large I think it's because the fluorescent options - or maybe more accurately, the options for line that shows up under black light - are really limited. I do believe this is changing as I think even some superlines are starting to be formulated to show under black light. Going with the idea that options are still limited, however, this means that you have to pick a line that you'd probably never pick otherwise just because it shows up under a black light. Add to this that I rarely have the opportunity to commit to night fishing for a period of time that's long enough to warrant replacing line that I like for daytime fishing (whether that's due to the line being overly visible, just not being very good in general, or what have you).
Additionally, I really don't see a lot of benefit in line showing up under a black light unless you're using a technique like drop shotting, working a fluke or senko, flipping, etc. where line watching becomes beneficial. For smallmouth especially, I'm not sure that's the best way to approach it except in rare circumstances. I think they're much more prone to roam at night, or otherwise maybe just don't find slow moving baits the same way they find something putting off a big thump or that's otherwise obnoxious. Largemouth are a different story as it seems they very often like to be up next to something at night time. This sometimes requires fishing slow to get bites. Accurately finding and hitting specific targets next to cover becomes an entirely new obstacle then, and it's one I've certainly never really overcome! I end up seeking out docks with lights or other cover with lighting nearby usually in those cases. I tell myself it's because it attracts things at the bottom of the food chain which eventually attracts the bass. While I think that's true to some extent, it's probably mostly driven by not wanting to have to try and fish blind in close quarters.
That said, if you have some extra equipment that you can dedicate only to night fishing for at least the part of the year where you're doing it, won't be doing much daytime fishing during some period of time, find some line that shows up at night that you really like in general, tend to use mono a lot and/or change your line very often anyhow, or something along those lines, I think it's a great way to go. Especially if you find yourself using techniques where line watching is beneficial.