This might sound petty, but the one thing holding me back from buying one of these is that it doesn't use a USB-C plug. Pretty much every piece of gear I now use from my Canon to my MacBook Pro, Gimbal, my Slypod to my Powerbank, and even my rechargeable flashlight all use USB-C for charging. That's great because now I only have to carry I cable around with me in my bag. But having to keep track of one extra cable just for this is a deterrent. Crazy, I know, but I sure hope some day you update it with a USB-C plug.
It's only a cable. Please understand that I'm a little manufacturer only and cannot easily change the port. First I need to sell all already produced units before I can think about a hardware change.
In my case it is the other way around: 90% of my gear uses Micro USB. Since years I always had to deal with different types of USB cables, so I simply do not care. And when Gunther decicdes to use USB-C with the ProTimer XYZ maybe next year, you can be sure that 2 years later we have another type of cable and the whole thing starts again.
For this reason I use a multi charging usb cable since a long time and therefore I need also only one wire to charge all my different devices (iPhone, usb-c and micro usb). May be also an option for you. The timer is really a great piece of equipment. Don‘t want to miss it in my bag.