It supports higher power delivery, is reversible, smaller, and -albeit with an adapter- fully compatible with USB A devices. It is the new standard connector for the USB- and Thunderbolt-protocols, and is even now used more and more often.
Apart from specific use cases where there will always be a need for specific connectors (and of course always the one that isn't on whatever device you want to use at the time), most consumers will not need dongles because most consumers do not really plug things into their computer. And before you respond with a variety of things you'd like to plug into your computer through USB, remember that "most people are other people". And for sporadic use a dongle will not hurt, especially since it's only for a transitional period.
When USB Type A was first introduced, it faced backlash from people who felt that it had no benefit over parallel, serial and PS/2 ports, and now they needed (gasp!) adapters. One solution there, was that these ports were featured on mainboards for a long time besides the USB ports (and these ports went unused in many consumer cases).
I am of the opinion that as long as there is one USB-A port, maybe two, on new device during this transition period, the rest of the ports should all be USB-C. And as soon as possible.