Is Hex worth it at high levels?

[diplomancer]

The book doesn't say anything, one way or the other. Here is the entirety of what the book says on bonus action re-application, "If the target drops to 0 hit points before this spell
ends, you can use a bonus action on a subsequent turn of yours to curse a new creature. A remove curse cast on the target ends this spell early."

There is no description at all on what it means to curse someone. As a player its nice to assume it's entirely mental because it opens room for a subtle application (of course I wonder how a player would feel about it in the reverse). But there is no evidence it means that any more than it means needing to repeat the casting V, S, M components without spending a spell slot. It also, doesn't say if the target knows where they are cursed, whether they glow in some odd light, does the outline of a skull and crossbones appear over their head? Or is there no indication at, all and you have to guess about the need to remove the curse? Hex is a great example of a spell without enough general description.

And ultimately this is another example of why what the book says is more guideline than some all encompassing truth to be hurled at people.

So what should it do?
Does the re-application have a verbal component? This makes sense more than anything else, cursing some someone traditionally isn't silent (though I could easily see ways to try and make it subtle).
Does the re-application have a somatic component? I could take or leave this, but since the spell does, it makes sense to need it as well.
Does the re-application have a material component? You're not really casting a spell, so I would rule no.
Does the spell have a visual component indicating its presence? I would say no, that feels too video gamey.
Does the target know they have been cursed? This is tough, I would say they know something is off, especially after they first need to roll with disadvantage, or take extra damage due to the curse.

You are free to add requirements that are not in the rules. But then you're following your houserule. You need components when you're casting the spell, that's all the book says,.not when you're using bonus actions or actions the spell gives you.

The book also doesn't say that you have to loudly shout whatever spell you're casting- not as its verbal component, just an extra requirement- so would you say that if a DM required that he would just be "making a ruling" and not creating a houserule?