I agree that generally a home inspection will identify a lot of things that are meaningless to an investor in a FLIP where you are doing fairly major renovation.
I think if you talk to your inspector and let them know what your plan is for the property they will focus on the items that could be potentially expensive to repair if you didn't factor that into your budget. In my area you can get an inspection for under $300. That is cheap insurance.
I also agree with the idea of having a general contractor view the home with you. They are able to spot potential problems and can also give you a cost to repair.
So that brings me to the question of which one should I hire?
IMO it would depend on the amount of work you anticipate putting into the property and whether you intend to hold it. If i were to purchase a fairly new property for a rental that needed simple updating (new flooring, paint, etc.) I would hire the inspector. I would want to know all the "little" things that should be fixed. If I were doing a major renovation I would hire the general contractor as I would want to know my repair costs.