Advantages and Disadvantages of each camera system
Advantages of the Smartphone that typically you don’t have with a DSLR
You always have the camera with you.
it is light weight and can fit in your pocket and easy to take on vacation.
It is multifunctional as you can check the web, talk on the phone and many other options.
Going from a Samsung Galaxy S4 to an S7
When it came to taking quick shots of notes I needed to remember and other things (especially inside or in low light) I found I’d rather use my point and shoot camera as I was always getting blurry images with the S4! This is better known as motion blur. The lens and ISO were just not good enough to freeze action with it unless I took a flash picture.
The camera on my S7 allows much more light in (with better ISO) and so no more motion blur! I stuck my point and shoot in my closet and now use my S7 exclusively for taking pictures of notes and quick shots. This is a much better camera.
Advantages of my DSLR that typically you don’t have with a Smartphone
I can change lenses. And the lens is the heart of the camera. Unlike Smartphones that do Optical Zoom, when I use a Zoom Lens on my DSLR it keeps all the pixels intact. Therefore I get a high quality image that I can blow up much bigger than an 8x10 print. With smartphones and optical zoom you lose pixels when you zoom. It is basically the same when you cut an image down in software. You see closer but at the expense of printing it large.
I can track moving subjects with my DSLR taking multiple photos quickly
The focus system can track and shoot moving subjects with blinding speed. Smartphones were just not designed for this. Even newer mirrorless cameras have a problem with this as well.
I can add an on-camera flash and also trigger studio lights with my DSLR
When it comes to inside photography an add on flash is a must!
As the smartphone flash is not that useful. There is not enough light coming from it to do anything but maybe light up a close up of something close. You cannot bounce flash or really use it to light up a large group of people. That is why I always recommend taking your groups outside in daylight if you want to do a group picture with your smartphone.
Anyway that is my two cents. Hope this educates you a little more on the subject. Best of luck with your decision on which to own. And yes, it does not hurt to have both!