Windows boot time will be faster & so will loading demanding applications. Also, if you're coming from a traditional HDD and switching up to an SSD, you'll notice games will load a bit faster.
although loading times between a standard 2.5" SSD and an M.2 NMVe SSD have virtually no loading time difference for games. I've tested myself on 2 different desktops I have(one with games on a Mushkin 2.5 SSD & one with games on a Samsung 960 Evo M.2 NMVe SSD). Both systems take nearly the same amount of time to load games.
There's also various Youtube videos of people comparing game load times between both types of SSD's and coming to the same conclusion.