A coin casino decide to accept on their platform may likely win them more users, and let me say that currently, I think. The hype around Trump coin have subsided, so I really do not think adding Trump coin to the casino at the moment will make any difference, but maybe it would have made some difference if they had added the coin at the time when the hype was still very fresh, this is exactly what Stake.com did.
Interest in the Trump coin may have reduced because it has lost it's hype, but that is not to say the hype will not return. One statement from POTUS and Trump may be back to moving to the last high.
I can bet you that there were many new crypto holders who Trump coin was their first ever cryptocurrency they bought into, and likely still hold, if any casino is targeting or has a target of bringing this type of people in as users, then adding the cryptocurrency they already hold is one of the best marketing.
There are people who still have eyes on the Trump coin and have it on their watchlist. They consider that the Trump coin will be relevant all through the tenure of President Donald Trump; they may not be wrong.