If you're connected to the Internet Windows 10 will update automatically.
The updates are mostly for 'security'. Internet security gets more complex all the time. Viruses and trojans and malware is a big business these days! But also Microsoft is famous for releasing products on a schedule, whether or not they are 'mature'. Finally they decided to fix this through automatic updates, so you can at least get fixes as they come up with them.
Do you have to do the updates? Well no, but you also don't have to change the oil in your car, buy a new furnace filter every year, wash clothes, etc. etc.