No one knows what the landscape will look like by the time the 2024 GOP convention rolls around. So, throwing hat in the ring makes sense.
Trump has lost control of the GOP, he retains the most influence, but that is not the same as control.
A recent poll had him at 42%, pretty impressive, but with DeSantis at 36%, that leaves 22% spread among the remaining potential candidates. That leaves a lot of room for political "horse trading".
Haley had 5% support, Pence 4%, Pompeo 4%, and the other 9% gets spread out pretty thin. The more you can crystalize your support, the more influence you have, when the horse trading starts. If Haley can get her numbers up to 8-9%, then in my opinion either DeSantis or Trump will offer her the VP slot. Which would position her for the President down the road, especially if she is Trump's VP and he wins.