Here is my opinion on all of this, not my opinion on your video, @exyle. I hope I am not wrong on my low level assumptions on the STEEM blockchain inner workings. You are a witness, or you were in a time, so please don't be too hard on me if I am very wrong.
As far as I know, when steemians upvote, they say "those are my VESTS -shares- on the Steem blockchain and I think this post/content deserves the corresponding share of the inflation of STEEM".
What Steem front-ends know for sure is the amount of Steem the post will get, according to the Steem Power of those who upvoted and taking into consideration the formula which allows to convert between VESTS and STEEM. That STEEM is normally paid in the form of Steem Power, some other times also split in liquid and non-liquid STEEM.
Fiat currency conversions are something fully outside the blockchain, and it will be fluctuating continually, adding complexity to front-ends, as your video is not the first one which tries to explain all of this, and will of course not be the last one. What participants will get is STEEM, for sure, while they will most of the times be unable to convert the rewards to other cryptos, as most of it will be rewarded in illiquid SP.
They would be able to convert 50% of the STEEM at the rate used to calculate the rewards, at most. So showing the reward in fiat is always lying to the user and the visitor to all of the Steem participants.
In my opinion, all of this could be simplified by just showing the amount of STEEM a post will get as a reward, which is certainly knew to front-ends without having to know the STEEM/USD conversion rate -being it from the witnesses data feed or from third-party websites like coinpaprika-.