Is Hex worth it at high levels?

[Segev]

I mean that almost every Warlock will feel the need to take it, by level 5 at the latest (by level 3 if it has the upcast feature). It's a straight- and significant- damage increase, kinda like Agonizing Blast (which is also considered by many a tax on Eldritch Blast builds, except this one applies both to Eldritch Blast Warlocks and Pact of the Blade Warlocks equally).

It's like the new Warlock they tried to sell, where Mystic Arcanums became invocations... but what invocation is going to compete with a 6th level- let alone a 9th level- spell?

If they're taxes, then, does that mean hex is just not worth taking as it is? Or are you just saying they're too strong?