think its a feature that VIP users only can take advantage of
boost is a form of a loyalty bonus to Stake's most consistent players , available in a form of coupons
it depends on your activity during the week and on your VIP status , some can get as much as 0.01 bitcoins ( if the Platinum vips didn't lie to me , haha )
the rules have been changed recently and now it is slightly different , focusing more on the bets you make , the volume etc.
become a VIP and find out yourself !

Best. Comment. Wins.

A 6.8k win, if not on Stake, how did you win it?
Could you be as lucky as this high roller?

yup , I'm a golden VIP as well
you should have access to the telegram channel then , think it is explained there in detail
plus Eddie should have lectured about it during his streams , in between betting copious amounts of coins( didn't watch the latest - guilty )
its the first time I hear about the "BOOST" button  near the vault on the menu , maybe its a thing that pops up at certain times during the day , gotta read more about it

❗️$1,000 race starts in 60 minutes❗️

Length: 120 minutes
Start: 2:00am GMT
End: 4:00am GMT
Prize pool: 2,500 XRP ($1,000)
Winners: 100

I got this boost feature after I talked to the VIP manager (Mia) through telegram. It is indeed like a faucet that can be claimed every hour, it is valid for a week depends on our activity during the previous week IMO. The amount is also depending on how much we have wagered. Once a week is passed then I need to request to activate this boost feature again. So I suggest you to talk to VIP manager or by asking live support to know more about it.

They used to have these boosts as well back in the day at primedice too but it was totally different. You played and wagered a lot, than you chat a lot as well basically doing all sorts of stuff to earn "achievements" and that helped you level up, if you leveled up enough your faucet grew, now there is no faucet of course and you only get to make free money by writing on their forum (for some reason) but that was the point of leveling up on primedice, to get more faucet.

The more you wagered the more faucet you got but at the end of the day the more you wagered the more you lost as well (thanks house edge) hence getting a bit more faucet made no difference to you since that wasn't even close to money you lost. At one point faucet abusers gambled a lot once and than only used faucet to make up the loss and than even withdraw some hence they stopped. Lets hope this VIP stuff doesn't become like that.

Wheel of Fortune | https://forum.stake.com/topic/25606-%F0%9F%8F%86-01-btc-garys-wheel-of-fortunewheel-challenge/

It's challenge time!
Cure Gary's hypnosis by stopping the wheel at the correct point!
There is a nice prize pool on the line too 😎

Nice work 😎 #stakerace

It is a wonder that people actually get lucky with these races. I mean when I try to get in there I fail to make that much bet anyway but even I lose more than they do at their wagered numbers. They must be doing something different than I do, I personally use the autobet maybe thats my problem, I should start using more manual bets and maybe then I can make tweaks and changes during the races.

I just put it on autobet with high chance of winning and let it run until the money is gone and I fall short of these wagered amounts because I end up losing it all (not gonna lie I play with 50 bucks and just put 10 bucks bets on 90%+ win chances and let it run until it ends). Maybe they play with a lot more money but looking at the winners it looks like the winner had only 4.5 btc which is really not that high.