the currency ingame is just your steam wallet, the way cases work from least valuable to most valuable, blue->purple->pink->red->rare(knife) depending on knifes they go from 30-70$-> 1k~ it depends on the style, theres also quality on all gun skins and knifes ranging from field tested to factory new i dont know the inbetweens but you get the idea, then theres also stat trak (counts kills on the gun and knifes) which also increase price, many knifes that are worth more than the steam price cab (400$?) are sold on alternate sites and you wont see them being sold on the market.
the guy who lost 22k$ was exactly that 22k irl, theres a lot of money involved because people drive the prices up of knifes because they look cool.
when doing csgo jackpot or other betting sited theres different ways to approach it, many people snipe or team up and bet big together. the idea is however much you put in you get a percentage, if theres a 100$ pot and you put in 10k cash you should probably win but theres always a chance you dont, what i see many people do is try to "snipe" meaning someone goes in 1-2k and they overdo it like 3-5k+ and you just pray you win, theres one site where people do 10$ bets and win really often, which is bull s**t because people will do 1k+. you have to be careful because they take a tax probabbly 5-10% not sure havent done it so if the pots not big enough you could potentially not profit, theres on site i dont remember who will absolutely give back when you put in then tax you on your winnings which is nice.
heres an example of phantoml0rd(his stream is literal aids) trying to go head to head with someone but you get the idea
if you ahve more questions i can try to explain i think i covered most things i suppose