Hallowed Mystery Master Bundle (£37.99)…
The wording on the Random chest makes it perfectly clear that you select six legendary gems (from the pool of all the 5-star gems in the game) and that you’ll get one of them randomly selected from the six you selected.
Hallowed Choice Master Bundle (£75.99)…
The wording on the Selection chest lets you pick one 5-star legendary gem (from the pool of all the 5-star gems in the game) and that’s the one you get.
There’s no deception. No wording indicates that you’d get six legendary gems. Also, why would you expect the cheaper chest to give you six 5-star gems, when the more expensive chest gives you just one?
It’s not Blizzard’s fault if players don’t read the descriptions of what they’re buying.