Same deal as lottery tickets, its a long shot for fun not any serious deal. You arent quite 100% on this across the whole site, I would estimate if a person became an expert in some way on the sports and events betting and you seriously have a better estimation then the crowd then its not impossible you beat the average and return profits on such time invested. Its still very tricky to rely on this in any serious way but some people have a gift in their judgement, many fail.
DOGE I was a miner long ago and its a testament to memes its carried on but I can well believe its got problems behind the scenes because when I stopped using it the protocol lacked a proper long term plan. Proof of stake coins is what I thought would be the ones to survive most easily, they are barely known except maybe ETH finally tests this idea and we'll see after 7 years is it a good system alternative to proof of work factories and energy usage. Beyond price, this will be something exciting in crypto I want to see transform.
I think it's quite obvious that a regular bettor who has gained a lot of money on other websites, that usually means that you have a chance that you could actually be great here as well, plus here you could gain some other stuff as well, so a person who knows sports and willing to gamble here would have a good time for sure.
Lottery on the other hand is just pure lucky, and there are regular people who just gamble and have few thousand tickets at most, and then there are people who go all out and buy like millions of tickets, I doubt that it would be possible for those people to gain that, have you checked how much bitcoins you have to wager in order to have 5+ million lottery ticket gifted to you? That would be insane, possible but insane, and that's why I think most of it was purchased. There will always be different type of gamblers, we will never know how many types, but I am sure people just like doing whatever they want.
you can also accumulate from their free btc as it will give you 10RP per roll, not bad. 
I had 50k+ RPs two months ago and decided to be redeeming them, from time to time, to be getting additional lottery tickets for each free roll, 100 TICKETS / ROLL, namely. No wins so far, but I still have 5k RPs, and keep winning good amounts of them on the Wheel of Fortune, so maybe I'll win more than 0.001 BTC with the lottery eventually. 
