How long will that roof last?
Why is the paint peeling from the siding?
Are the windows (doors) rotting?
Is that wire the proper size for its circuit breaker?
Is the furnace flame supposed to be yellow?
Does that crack in the foundation mean the house is about to collapse?
Why is there moisture in the corner of the basement?
If you know the answers to these (and a hundred other) questions, maybe you don't need a home inspection. In fact, maybe you should become a home inspector yourself!
On the other hand, if you're not sure of the answers and have some questions of your own, a home inspection will help you to understand how your new home works and what may need attention--now or in the future.
The most important product that your inspector has to offer is peace of mind--the feeling that you know what your are buying and what its strengths and weaknesses are. If he feels that some of those weaknesses require further evaluation, he will refer you to the appropriate experts. He will let you know what routine maintenance is required for the various systems of the house. If there are safety issues, he will point them out and tell you if they need immediate attention.
A home is probably the most expensive purchase you will ever make. Be sure you know what you are getting!