Seems a bit silly to me. I don't see that there is any added value to these. One can create the same thing on their own. I was hoping that they had new effect or amp sims, not just patches using the current assets. Oh well, I guess if they have what you want then there is value there for you.
I've never bought a pack of presets. However, I can certainly see how somebody would find them valuable.
These units, especially the higher-end ones, can get extremely complicated in the process of creating a patch. Not that it's hard to put them together
per se, but it's hard to tweak them and tune them and get the sound you're looking for. This is especially true when you get to the units that have IR loading, separate amp and cab models, mic models and parameters to change the placement of the mic, global parameters like EQ and input pad, the ability to create parallel paths, and on and on.
As an anecdote, a lot of people went on the Helix boards and complained that they thought the sound sucked. Like, they loved the sound of the demo videos, but got theirs and couldn't get a usable tone out of it. Harsh fizz, boomy bass, clank... The problem wasn't with the unit, the problem was that building a patch up from scratch requires knowledge beyond what you would need to know to set up a chain of discrete pedals going into an amp.
Aside from just getting past the sometimes daunting task of getting a good initial basic sound, there are some people out there (Glenn Delaune comes to mind) who are absolute wizards at getting multi-fx pedals to create rather amazing sounds.
So, to each their own. I've never bought one, but I like that they're out there.