That's exactly it. It's gambling, plain and simple. Sometimes you can make a few grand, sometimes you can go a few grand without winning. I know a few people who do it almost exclusively and losing £10k+ is a drop in the ocean to them.
Also keep in mind that there are quite a few people about who like to suck themselves off for epeen and will spit out any random numbers to make it happen. Loads of BSers out there, be very wary of it.
EDIT: Just to clarify, the nonsense epeen aspect comes in many, many shapes and flavours. Stock traders, crypto traders, sports traders, lottery players, people lie about everything. Just look at people who post about how much money they earn. Most people on decent money won't discuss it, those who do usually do it out of an inferiority complex (not always the case, but I prefer to put it all in the "BS until proven otherwise" bin). Same with people on winning strategies for making money. They won't share it as it makes them bank and they don't want it nerfed. Just like those pro-tipsters on Facebook. It's all smoke and mirrors. If they were actually able to make money reliably on their accumulators they wouldn't be trying to make money off of selling their tricks.
The old adage always applies: if it sounds too good to be true, it is.