I don’t understand how anyone manages their money and how they want to use it when medical expenses are concerned.

Your “how I want to use it” is completely out of your control and based on when you fall sick, get injured, need advice, etc. Nonenof which are choices you make. So even an extremely efficient entirely private system doesn’t allow you to either manage your money nor allow you to choose how you want to use it.

You could take insurance, but again, you’re neither managing your money nor choosing how to use it.

Medical expenses are not like buying a toaster that you can decide to put off or buy whenever you want or never if that’s what you prefer.

Also, in any modern decent society, if you choose never to eat toast no one is concerned. However, if you’re dying on the street because you aren’t paying for medical care society will step in. So there’s also a burden you’re imposing on society based on your choices that are not involved in most non medical situations.