I am looking at the new signatures and can't help to feel that more emphasize could be given to the onion link instead of the clearnet version of Sinbad. Only the part on the far left with the skull contains the TOR link, while everything else has the clearnet link. As a compromise, perhaps the far right box (MIX NOW) could also point to the onion link. That way we would have the ends of the sig pointing to the onion link, while the center of the sig contains the clearnet link.
I would argue that decision is very dependent on the usage profile. I have no idea about percentage of people that access sinbad trough TOR, if it is small and I expect it is, I would argue that it shouldn't even be in the sig or that it should have been clearly marked as TOR link.
My logic is that those that want to use TOR are usually expert users and will find their way to needed links while there is certainly some amount of newbies that could simply go to competition since they would think the page is not working after clicking on TOR link.
Those long-time users of mixers already know that there are Tor versions so they have Tor on their device, but those who just want to use Sinbad Mixer for the first time and may not have Tor on their device will think twice about using Sinbad.
The clearnet already has a Tor link and it's visible on the homepage, the clearnet converts new users to use Sinbad because of its accessibility.
I'm sure in their panel they can monitor what versions convert more users, and besides the competitors are also using their clearnet version in their signature.