The machine might boot more quickly.
Well, you've named one big advantage for a start (and then dismiss it, although it is important for a lot of people - I certainly don't want to go and make a cup of tea every time I restart the computer).
Windows 10, I find, is more responsive than 7, and it is easier to find applications on it. Cortana is a great improvement over previous search engines - assuming that you don't wear a tinfoil hat. Live tiles are great, allowing a quick view of weather forecast, news, new emails, etc., etc. without having to open an application. And, having got used to it, I far prefer the flat look to the skeuomorphism of Windows 7 and earlier.
It's just the entirety of little improvements like this that make for a more pleasant and easier experience. For me, personally, the fact that Windows 10 integrates so smoothly across a range of computers, tablets, and phones is a big plus. Not such a deal if you are an iPhone fan, but I like my Windows phone.
Plus, I've not managed to crash it or lock it up yet; it's easily the most stable version of Windows that I have ever used.