Several Casinos leave the withdrawal fee to the corresponding network, it is not that it is free, what happens is that they do not charge an additional fee to process the withdrawal faster. Check what type of address they use for deposits, this can be a good indication that your withdrawal will be processed within the estimated times.

For other casinos you can see this summary: https://bitcointalk.org/index.php?topic=5333602.0 where by the way this casino does not appear, but if you check it with the live chat and confirmed that information, it is surely so.

A 6x is quite low for the average of the demands in the casinos, but remember that they can be enough to "water" your deposit, caution and experience together are the best rollover.