The biggest buck receive those affiliates whose websites get organic traffic from search engines on keywords like best online casinos or best online casinos + location. Also, very good are online casinos that accept Paypal, Bitcoin, Trustly etc.
Such queries type in not only "small players" but also high rollers and all traffic from there go to affiliate sites that sit on the first 3 spots of Google search or to those that have the most attractive site titles within top 10 results.
For the most part, big players are not stupid and before a game, they look for information including guides, strategies, payment methods, withdrawal times, terms&conditions etc. I this case, those affs at the top of Google search on the topics related keywords will receive all the traffic.
With streamers is a different story. As a rule, their traffic is cheap (low quality). And that's because of the fact that among those people who watch streamers are many who have no single penny in their pocket.
Also, are tons of those whose main target is to take advantage of streamer's exclusive bonuses (free spins or 200% first deposit bonus) and in case of loss or win never return to a casino again.
Instead of signing up through a streamer's link, many viewers would type in a Google search bar a name of the casino or that casino review.
This option would show them websites that Google thinks can answer their query the best and, as a rule, top affiliates or official casino sites would take all the traffic again.
So, I would not advise you to start streaming, mate

.
You can still become famous and popular by delivering a super-exclusive content on any other subject too