Yes, the engineer survey is just to satisfy the bank, and more often than not it just reassures the bank that the property actually exists. The valuation they attach to the property as part of the survey (at least used to be) suspiciously similar to what you are actually paying for it, as if these guys actually know anything about property values.
(S)he would would almost certainly not have caught the sewage or electrical problems, and even if they had, it would probably not have made a shred of difference to the transaction - unless it would have scared you off.
The surveyor is supposed to work for YOU, but most people let them away with murder. I've bought property without a survey because in all honesty I can do a better job (in terms of satisfying myself as to the property's structural state) myself.