The fact that it IS a dongle is the major disadvantage. Most laptops have only one or two USB-B slots and many are moving towards USB-C for everything. Most also have very functional bluetooth built in. It's just not worth a minor improvement in connection quality (which is debatable, reading these comments) to lose the only slot I have in a laptop. I have to unplug my external keyboard in order to use my headset if I'm not using a dock. This was enough to make me spend my own money to replace the logitech mouse I was issued at work.
I have a MX Keys and it works with the dongle and bluetooth, your choice. I have both the mouse and the MX Keys using the dongle connected to my display's USB hub so the mouse & keyboards are always there for the cmputer that gets connected to the USB-C cable. It's uncredibly convenient.
This is my exact reason for going Logitech keyboard and mouse. I have a work Mac and personal PC. With a thunderbolt dock I can use either one at my desk. I don’t have to fiddle with pairing anything, just plug in the computer and the keyboard and mouse show up. If I travel then I just pack my mouse and pair it with my laptop via Bluetooth while away.
*USB-A, the B ones are for devices, i.e. what you typically saw (in the micro variety) on cell phones before UBS-C started happning. The big "original" USB-B ports are still common on printers.
Then the question to ask is why Logitech STILL doesn't have USB-C dongles?
The ability to combine keyboard and mouse into one connection is a huge selling point, and Bluetooth sucks. But Logitech is merely coasting on its fading brand, not even bothering to update its connectors.
My k860 and MX Master does not need the dongle, although I find I get slightly lower latency with it than with regular bluetooth. I leave it plugged in to my docking station and switch the mouse to bluetooth if I take it to a conference room.
I plug in 3-4 cables on my laptop a day. I don’t see why plugging in a dock is so difficult. Hell all you really need is a USB hub that connects via USB-c. One cable and done.
