Maybe Eccleston didn’t believe the reboot of Doctor Who was actually going to work. Think about how little Patrick Stewart was prepared for Star Trek: The Next Generation for the first couple years. It’s just a TV show to some, most eventually grow to love the role, but some just don’t.
I think there’s been a tradition since TNG of giving the casts of the newer Treks a friendly warning/heads up of the craziness that’s about to enter their lives.
If they have any brains, they shouldn’t need a warning. Everyone not living under huge boulder knows what Star Trek is.