HSA might be nice for routine doc visits, meds and some testing, but nobody can quickly put away what it takes for a major hospital stay.
Also, the insurance company would negotiate the prices for me. I had a high risk pregnancy and delivery with a preemie in intensive care and a hospital bill over 60 thou. HSA 'negotiated' that down to 12000, and then paid almost all of it. I don't need insurance, just those insurance negotiators to get my bill down to something I can afford.
Now I have signed up with a HSA through my employer. The difference is that the employer pays into the savings account and they keep the difference. This works differently in that every single thing is paid for until I get over the savings amount, then I am in a donut hole until they cover everything again. But, it is the cheapest plan the company offers, and I haven't made it to the hole, yet.