I also didn't wanted the funds immediately so i opted for the low fee option but luckily out of my expectations it got confirmed quickly.
All of you guys are getting instantly because of two reasons; First of all roobet is saying "low" but in reality they are paying a decent amount even in low, sure it may not be instant all the time, try the low option during periods like 32k to 40k increase period, when bitcoin price went that high that quickly mempool was filled with orders and it got super high, so that low was actually low for a while, and even at that moment it was at least few hours but not more than 4 or 5, it was still done within like 3 hours for sure.
The reason for that is they can't allow you to do like 10 satoshi payment, because we all know it would either take years, or it may even never get picked at all, so they do not allow configuration like that and do a decent low in order to pass, just so that gamblers do not start complaining from slow process even though they picked low.
At the end of the day a "low" is a "low" and as long as it is fast that shows how great roobet could be. Obviously it could take long time and if it takes long time nobody can say a thing, because it is a long time anyway, but if it takes a very quick time that is a good thing and that is what people really like here.
Think about it this way, if there is something bad you expect, like let's say you took a test and you expect to get 20/100 from it and fail, if you actually get a 20 and fail that would be what you expected and that's it, but if you get 80 you would be suddenly very happy. That is the type of situation we have on roobet withdrawal right now, it looks like it is bad because you pick low so you think it will be there very very slowly and if it is ever very slow that means you expected it and there is no problem about it, but if you get it very quickly you will be extremely happy about it.
;D. And right now it has a shorten timeframe considering the past art contests that we've got a month or 20+ days to think or execute art pieces of every artist. I Will not miss as well this one too to submit my not so good arts but loving the thrill if I win or not. 
so luck to those who chose the most approximate guess in their calculations in this special event.
