A couple items to consider in my opinion. Can u benefit from the long-term gain tax free? If u r OPT, u may need to withdraw the money out within 24 months if u r not able to secure a full time job. I don’t think that make sense to go through the troubles. If u r on H1B and u believe your job is stable enough for a least the full H1B life (6 or 7 years), then, it start making sense. But u need to read your company’s plan and calculate the math to see what’s the benefit. The benefit of HSA is surely there, if it makes sense for your situation (i.e. healthy single individual + your company also contributing money).
Forgot to mention some companies will contribute money into your HSA account (i.e. Apple). If u r a healthy individual, the company contribution can cover a large portion of your annual medical needs (90+% in my case including preventive prescription drugs). That leave almost all of my personal contribution saving. So read your company’s benefit plan in details and it can help u plan better.
If you invest 7K for 30 years, with annual return of 8%, you should have sum of about ~925K tax free for medical expenses. That should cover major portion of medical expenses for you and spouse in retirement .
This math assumes annual contribution limit stays at 7K, it wont. You don't have major medical expenses during these 30 years, you may. HSA Laws don't change, they may. But considering social security benefits to wane in future this should be a good backup plan.