They’re just connectors. Instead of having the PCB traces routed to a USB-spec connector, you can use a Lemo port. Most boards just need four pins (power, pair of data lines, and ground) along with a pin for the drain wire.
This looks like a nice design, but the non-standard connector is going to be a deal breaker for me. All my keyboards have standard connectors, and I’d be pretty happy to keep it that way. It’s bad enough needing to keep three standard cables around, the last thing I want to worry about is a proprietary USB connector.
But at the end of the day it’s just a fourth cable to keep around. We already have mini-B, micro-B, and type-C cables, now there’s this one too. It’s a connector, how much can it cost? A good type C can be like $5
Lemo connectors are really expensive, you can customize cables on Zap with Lemo connectors and the cable ends up being $100+. This connector is modular so you can just swap the cable ends for the other USB variants for your other boards.
The male and female connectors themselves are only $25-$30 each. Ideally, the addition will increase the cost of the board by around $60 without factoring in the cost of cable assembly.
I was about to say, easy enough to look up the connector, it’s about $30. Whatever rocks your boat, but as I said before, definitely a dealbreaker for me. This looks like a really nice board otherwise. What is the appeal of the connector? It’s not a great real world metric, but it’s rated for half of the number of insertions as USB-C (5,000 vs 10,000). Especially at this price I can’t see any reason why it would be preferred over USB-C.
The choice is purely aesthetics, but I see where you’re coming from. That’ll probably be one of the reasons that hold me back from the board too because I already have a great modular cable for my USB miniB and C.
At the end of the day, it is the designer’s choice.