Is it really that much of a big deal? I mean do you really have no self control over when you will be selling and when you will be holding?
In the same way some just can't get away from gambling, some just can't HODL.
Even more, especially when the price is going down, many are getting scared and sell.
So
use cases for this do exist, even though, as I already said, it can be risky for when one really-really needs that money.
Still, as long as Bitcoin itself has tools for this, using something external makes not much sense.
Shouldn't those people need to learn a way to hold, instead of trying to wait to keep them from having that option? I mean there could be some serious reasons why they should sell. Like let's say there is a health issue, you have to be in hospital and pay a good sum of money to survive, shouldn't it be better if you could reach your money that way? Or there is a debt that you can't pay, I should know because I am in one right now lol) and then you will need to cash out.
Like for example, I have some saved aside, but by the looks of it I will be forced to sell my coins (some of them not all) just to pay my debt. Learning how to hold should be more important than preventing from cashing out.