I don't know if my explanation will help, but here's how I think about and how I"d explain it to my mother if needed.

Steem is a currency, just like the US Dollar or Mexican Peso. And like the US Dollar or Mexican Peso, it can be used to buy goods or be traded and exchanged.

"Steem Power" is a Savings Account that earns interest and let's the bank make loans.

"SMTs" are tokens that use the underlying infrastructure built by Steemit. They're a tradable, liquid good. Imagine going to a festival where they sell "Festival Dollars" that can be traded in that festival like money. Same thing.

This is all different from a points system in that the tokens and Steem are liquid commodities and currency that can be traded and sold for other liquid commodities and currency. Points on a credit card are not liquid currency. They're not even that liquid.

As for creating a Steem account and using it... yeah... that needs work. I actively wanted a place that wasn't Facebook to share my random thoughts, so I was happy to wait. I suspect most people aren't. And considering many people have a hard time remembering passwords, let alone four different keys for four different purposes, and we have a confusing interface. Fingerprint readers would be awesome, but certainly difficult to distribute. Maybe a good Two Factor Authentication system would help. Hmmm.

Performance of the Steem coin is also an issue, not only for users, but for all crypto. In my mind the biggest obstacle to taking crypto more mainstream is its volatility. 5-10% price changes daily, or hourly, do not make for a stable currency that can be used by the masses. I don't have a solution for that.

Anyway, hope this helps!