I'm also somebody for whom the steem blockchain was the first foray into cryptocurrencies. I have never invested fiat into it and I recently had my first bitcoin transaction as I finally needed to withdraw something from my steemit funds. If there was no need for it in my life, I would have continued to power up like I had done until recently.
While SBD is currently overvalued in my opinion, I think Steem's value will continue to grow in the long run and I would love to hold on to as much as possible. But the greatest value in it that when it's powered up, it allows you to give those awesome valuable upvotes that feel free.
And yes, there is a huge psychological difference between upvoting and spending fiat. Nothing in your balance decreases when you upvote, you only loose voting power and that regenerates itself. The feeling is great and it does not have a real psychological cost like spending a real dollar.
I try not to think about the money when I interact in the steem blockchain, but it sometimes comes into play too as monetary values are something you can see absolutely everywhere you look on the platform.