Well, first off, the Arcade Card does not have 17.5 megabytes of RAM. That would be awesome for sure, but...anyway, whatever. A byte is not a bit.
Also, its Gate of Thunder. Not Gates. That's a common and forgivable mistake most of the time, but when you have a video clip of the title screen that appears just as the guy says, "Gates", it's pretty dumb.
The 3x3 Eyes thing is unique. No other PCE game has a cut scene like the opening for this game. There are other games that are Super CDs with special features only accessible when running the AC, but they are nowhere near as impressive. Some are nearly impossible to detect.
As for faster load times...if you've actually run 3x3 Eyes on a real system you'd see that the load times for the AC version opening scene are HUUUUUUGE. Like, probably a minute or so. The SCD version loads way way quicker. The AC doesn't change the speed of the bus, the CDROM2, or anything else, it just gives you more RAM. If all of that RAM is going to be used, then its going to take more time to fill it. This is why most SCD games have pretty good load times; there just isn't that much to load. Compare this with, say, a PS1, which has about the same amount of RAM as an AC equipped PCE, and you'll see that the load times are still pretty horrific because the PS1 only has a 2x drive.