This is one of those areas where Rare has trusted players will figure it out for themselves.
They won't. I know because I raised this point over a year ago, and still meet many players who don't know about gold rush, some of them even 1 year+ players.
https://www.seaofthieves.com/community/forums/topic/133082/psa-regarding-gold-rush-hour-suggestion-to-change
Granted, many unaware players are new, and probably will eventually learn about gold rush. But probably from someone else. If Gold Rush was adequately common knowledge, those players would have learned about goldrush very quickly, within a few days at most, right up there with cutlass dashing.
Other players will eventually tell them, sure, but many players just chalk up the extra gold to something out of their control, like a bug, not realizing what they are missing. The info is too far buried in the menu, and the timezones really should just be standardized, or just localized within the game itself to the region you are in. Daylight savings in the US presents a unique challenge to telling people exactly when gold rush begins, but it doesn't need to be this way.
Having a prompt, even a minimalist one when turning in will help mentally cue someone into investigating it further. If the text was a different color when turning in, gold maybe, this would probably be enough. Within a day, there would be google articles informing players what the gold text means, whereas now, it is very difficult to figure out why you got extra gold, or even figure out how you should search for something like that.
But the holy grail would be to let players know a gold rush is coming up in-game with a prompt, so they can plan accordingly, either to hold their loot, or prepare for PvP. This would take a bit more finesse to not make intrusive, but would be worth the effort.
For dedicated players, Gold Rush is more than just a nice-to-have boost. It provides structure to turning in and organizing a crew around a set goal. It helps motivate the crew to accomplish more, and provides some strategic choices around which voyage to undertake, or whether we have time for a detour. These are the choices that make the seas feel dynamic, and I want others to experience that same feeling.
I think it would help some new players find some purpose/direction when first setting sail in Sea of Thieves, and which might help them stick with the game long enough to see what it has to offer.
It also incentives crews to hold onto their loot which helps gives PvP meaning.