A pre-purchase inspection is never a waste of money. Particularly considering you're spending $1,000's on something you expect should last a few years at a minimum. I'm unsure how mobile services work, but I chose to take mine into a Chevrolet dealership and have one of their technicians inspect mine before purchase. I would recommend an appointment since it can take a couple hours but they do inspect the car including computer diagnostics, and mechanical inspections including checking the drive train, suspension, brakes, etc.
The car does provide a lot of information through is seemingly endless list of driver warnings but it can't inform you of worn items such as suspension components, odd tire wear, seizing caliper slides, etc. This can only be seen through a visual check and can turn into costly repairs if left too long. Hope that helps.
