Pharmacogenetics personalised medicine: new frontier or nonsense?

Apparently my private health insurance covers pharmacogenetics testing to find the best ADHD medication. What is it, is it legit? What's the company going to do with my cheek swabs? How do doctors feel about me going up to them and say hey internet pharma bro tells me I should be taking this instead of what your years of medical school thinks.

What I can't figure out is how my insurance company benefits from this. I'm not paying extra for this service so I must be the product right? Here's part of the marketing FAQ info from my insurance provider:

Personalized Medicine uses advanced pharmacogenetic testing and pharmacist assistance to find the most effective medication for you.

If you’re starting a new medication for a mental health condition (such as anxiety or depression), chronic pain, attention deficit hyperactivity disorder (ADHD), or neurological conditions – or taking a medication for one of these conditions and it’s not working or causing side effects – Personalized Medicine could help. It’s offered through your extended health care benefits plan, so the cost of the test may be covered. To see the list of drugs tested, click here.

It involves a pharmacogenetic test. This is a type of test that identifies how you may respond to medications. Your test results are only for you and anyone you give consent to share them with, such as your doctor. The test is run by Personalized Prescribing Inc., a Canadian company. Manulife