Do you have a perceived difference between Steem and fiat? Why?

Yes, I don't know why. I'm new to the cryptocurrency world and I'm as same as you, I used some SBD that is actual money for making a token on Bitshares.

Do you have an easier time handing out upvotes, or do you consider their monetary value in terms of pool reward distribution?

I actually don't, mainly because of my vote worth almost nothing. I give my upvotes to a lot of people. because, why not? I don't lose anything for doing it, only getting curation reward and rewarding content creators as well.

Do you prefer to hold Steem till you need the cash or convert everything to fiat as soon as you can?

I always convert the Steem to BTC and ETH, and keeping them in my wallets. and I tend to convert a low percent of it to Fiat.

Oh and btw, This is the sentence of the century -

Today I purchased a mobile app for 2.99 USD. I took some time to consider this purchase, and after weighing the cons and pros for a few months (!), I eventually clicked the button to buy the app and rewarded the developer for the product I got. Shortly after, I read and upvoted a Steemit post at 100%, giving the author close to 13 SBD in payout without spending more than a second considering it.