In my opinion, it would be a good idea to replace the dollar sign with another symbol like PeakD has already done. The reasons are the following:
The Hive Token Unit is not equal to the US dollar
That figure is nearly always inaccurate. That's mainly because the Hive Backed Dollar is not equal to one USD. The total rewards in dollars could be vastly greater if HBD trades much higher than one dollar, which was the case between November 2017 and July 2018 when Hive was Steem. HBD (SBD at the time) quickly shot up to $14 and spent over six months at several dollars per SBD. The assumption that HBD is worth exactly one USD is baked into the definition of Hive Token Unit.
It's also possible for the front ends to overstate the rewards in USD. That happens when HBD trades significantly under one USD. That has happened around Christmas time in 2018 and in 2019 when the price of STEEM was so low that the market cap of SBD exceeded 10% of STEEM.
It's not good for Hive the economics to be too conspicious
Despite the fantastically high rewards relative to the visibility of the content on Steem and now Hive and the lack of competition over the rewards and the rewards thus being a long hanging fruit, this state of things has failed to attract the masses to Steem and now Hive. Against what common sense dictates, people who want to earn a side income from their content creation on the Internet aren't flocking to Hive. Instead, the rewards have attracted a lot of spammers who have sought to earn small rewards with automated spam. I really do love the concept of no threshold for earning but I think the monetary side of things being too in-your-face merely distracts people from content and engagement.
Also, I think the dollar sign is prone to (subconsciously) intensify feelings of envy some people harbor against the high earners. If the dollar sign is replaced with the HIVE symbol like PeakD has done, the rewards will be less of an affront to some people's sensibilities. Thus fewer people will be badmouthing the platform on it and outside of it. This is a problem that no mainstream platform has because the monetization is kept out of sight of everyone except for the author and the platform. On Hive, all the financials are public at the blockchain level and they also must be public at the front end level for Proof-of-Brain to be able to work. But I think all the other front ends would do well to follow PeakD's example.