Yes, I am shocked at all the criticism.
Yes, these are just the same indexes as on FamilySearch as far as I can see, but, with the addition of several levels of search refinement, including the one that most people who struggled with the marriages on the FS index have asked for, the possibility of seeing all the options of the possible spouses that appear on the same registration page.
There is, what appeared to me, a clear, and fairly large print, explanation of this information. Is it that this database has attracted many searchers who are not already familiar with the pre-1912 UK BMD records?
The fault seems to be in that they have tried to explain why there are options, rather than just waiting for those who haven't previously used a BMD index to come and ask us here on RootsChat!