>>4168036P mode and auto are for when you want a picture of acceptable quality really quick. Like, if there's a lot going on in a lot of different directions and you don't have time to set up your settings perfectly for each one. If you have the time, always go for manual, though I have had some use for shutter and aperture priority from time to time for similar reasons. I think it's just for noobs and lazy pros who know 99% people won't notice or care as long as it's crisp and in focus. D3500 is a fine camera btw. If you're moving to digital it's a cheap way to get lenses that cover a wide range for almost every use case. From experience, they aren't great for low light, and I've had some weird issues at super telephoto ranges, but the color and IQ are still really good, and a 35mm 1.8 is still really cheap for the occasional low light portrait. I did find that nailing focus on that camera can be tricky, however, and really sharp images are hard to capture with the cheaper lenses, but if you're coming from film you won't notice too much. A lot of what makes a digital image special comes from editing, so get familiar with that process.
