My experience in IT in the UK is:
VC backed companies will sell you private health insurance as a perk. It is rarely useful. I suspect it is a way of funnelling money at low rates of tax to the VC's other holdings in at least one case, but have no proof. It certainly funds the privatisation agenda at low cost to the investor, though.
Seniority is signified through leadership or contracting. The latter you can get private insurance as a perk through your own company, but again, it is useless.
Most permanent non-lead roles I've had that have been more conventional haven't had it, though.