I don't understand the appeal of a board like this.
Chess.com Support for Millenium Exclusive and King Performance via ChessLink

Some players enjoy OTB play more than on-screen play, and this type of board provides that capability. It also allows users to see the moves via the LEDs vice requiring a system that announces moves, or requires you to look at a screen (defeating the purpose of an encapsulated chess computer in online play).

I like the DGT solution:
https://www.chess.com/forum/view/chess-equipment/dgt-play-is-enabled-in-chess-com-beta
Next step is the support of the DGT 3000 chess-clock and everbody will be happy. :-)

It is still in progress, unfortunately. Besides, to play the DGT solution, you have to have a computer screen (right now). The best you'll get is it announcing moves. However, the DGT solution is pretty expensive - you'll need their board, their clock, and probably speakers. With the Millenium board, you can do it for a little more than half the cost of the DGT board alone. And you don't need the screen or speakers.

certainly would bring me here to play a lot more if there was connectivity to the Millenium chess computers

It connects a real chess board to the internet, or in this case Chess.com
It's a third middle device between a USB board and the computer?

+1 here as well, I have a DGT Board as well as a DGT Pi but the Millenium Exclusive with it's 81 led's is really nice to use so I would be happy to see a connection to Chess.com

Since you can now connect the Millenium board emulating a UCI engine, I think the chess.com connection is fairly close.
Lars Nowak an independent developer developed the pseudo-UCI interface which allows the Millennium ChessGenius Exclusive or King Performance module to interface with any chess GUI that supports UCI chess engines. But it looks to only be tested with Fritz and Arena at this time, so hopefully chess.com and other popular sites won't be too far off.
It would be great to see Chess.com support for the Millenium Exclusive and Millenium King Performance electronic chess computers via the ChessLink device. If Chess.com was willing to develop a protocol that would allow it to communicate via the ChessLink, all of the Millenium-series boards could be used to play Chess.com games online.
Here's a link to the ChessLink device: https://computerchess.com/en/chesslink-3/
*** Note: I am not paid for or sponsored by Millenium, I just love their product and really, really want to play games with it using Chess.com (my favorite chess site)! ***