Sweet potatoes do bloom occasionally, some varieties more than others. I have been breeding them from true seeds for
several years and other than a genetic component I still do not know what environmental factors encourage blooms. Some do it later in the season that others, but I've also had them bloom when just small seedlings. I'm also aware that they do bloom more freely in longer season, warmer climates such as yours. It may be that day length or just a longer growing time can influence blooming in some varieties.
They have very complicated genetics which makes breeding a bit frustrating at times but also lots of fun and even with those years of watching them I can't even guess why a variety that never bloomed before is doing it now. But there is no reason to remove the bloom. Even those that bloom a lot and actually mature seeds, suffer no reduction in yield. If the bloom isn't pollinated it will just fall off.
Because of their weird genetics they are generally not self-compatible, but some are, if you have a nice population of
bees and the like or if you hand pollinate you might luck into getting some seeds. If you have more than one variety and they bloom together, you have much greater chance of getting seeds.
Also because of the weird genetics every seed grow plant is a new and
unique variety, even if it was
self-pollinated, ain't that a hoot?