Some players use this type of bet a lot, I do not like to steal initiatives on flops, and you?
Indeed it's not the most common strategy but one that has value nonethless
In deep stack situations as other poster have mentioned in this thread
GTO likes leading out from the big blinds when the flop is all low cards
why?
The raiser rarely if ever has these cards in their hand and thus other than the rare set they won't be able to take much heat on these flops.
If you're holding even a pair and a gutshot it gives you a way to control the growth of the pot, price yourself in, and not get blown off your hand. (A thinking opponent will not be able to raise your bets because it's possible you actually hold the nuts).
This was also common to do in spots where you want to check-raise, but you don't expect your opponents to make a continuation bet on that particular board texture. It's a good way to ensure money goes in the pot when you had either a strong hand (which could become second best on bad turns), or a strong draw (which would lose a lot of equity if the turn is a brick)
Leading out on turns that favor you but dont favor your opponent is also a nice strategy to mix in. It puts opponents on the defensive and prevents them from pot controlling, or just controlling the action in general.
Again, these situations won't come up very often, but when they do it's worth making the play
Examples are when the middle or bottom card pairs on a board where you can have 2nd or 3rd pair but your opponents range is mostly weighted towards top pair, better, and bluffs
Finally, against opponents who just hate donk bets, and feel the need to raise them whenever they see them... well... this is a good way to get some extra money in the middle against them
I like being willing to do some leading (the other name for donkbetting) because it keeps me open to all possibilities and doesn't get me stuck in a limited way of playing hands