Overkill never hurt anybody. Would you really want to ditch the SSD even if no other numbers changed at all? Even if you don't need it, I don't see why it's a bad thing.

It's just overkill to me to pay $20 a month for this when I expect a non-SSD plan would be half as cheap, if not more.

You can go with Digital Ocean or one of the other providers in the $5/mo range if price is your real concern here. That's what they're there for. No need to go through the indirection of talking about SSDs.