Anonymity
When users play at a traditional fiat casino, they are required to provide the platform with a range of personal information. Moreover, they are expected to upload multiple documents such as a passport, proof of address and a copy of the payment method used to deposit.
On the contrary, online casinos that specialize purely in cryptocurrencies are not required to follow the same set of regulatory red-tape. In most cases the user is required to supply nothing but an email address, subsequently facilitating an anonymous gambling experience.
While it can be appealing to many people, this feature is what makes it so easy to go for money laundering this way, and that brings cryptos bad reputation.
Trust
When playing software games such as blackjack, roulette or slot machines, there is no way to verify that the fiat casino is playing fair. As a result the player needs to trust that the odds on display are legitimate.
This is in stark contrast to a cryptocurrency casino that implements a provably fair protocol. Provably fair is supported by the art of cryptography - meaning that each and every gaming outcome can be guaranteed for its fairness. Moreover, this gameplay data cannot be pre-defined or manipulated by the casino.
It is indeed easier to make sure the casino is provably fair when it is online, but at the same time there's much less risk of getting scammed in a traditional casino, so there're some trust advantages there as well. If we are talking about casinos operating on smart contracts, of course, then the advantage is definitely on the side of crypto casino once again.
I think that some people would still opt for land-based casino for such reasons as getting to know people, drinking champagne and controlling the funds more seriously than during online experience. But surely online casinos are very cool in their own way.