&gt; But if the only way to use it is for medical expenses then why is it so beneficial especially if you don’t have many medical expenses or if you’re not close to older age where you’d have medical ailments?

1. You can reimburse those expenses at any time.  Have a doctors visit today, but take the money out of the HSA 10 years later.  

2. So you have more money to cover medical expenses when you are older or do have issues.

&gt; Also what growth?? My HSA doesn’t grow unless I put money in it.

You need to invest it and not just leave it sitting in the cash side of your HSA.