I hear all the time how phones are becoming the new DSLR with its high tech camera. For a while I agreed because the cameras were getting much better. Yet, with phones, you won't receive that high professional look.
Professional photographers craft their skill for years and perfect it along the way. This includes settings to have the camera set on, location for photos, and the best angles. A phone doesn't allow the manipulation of settings for depth of perception, lighting or focus.
One aspect I have heard from my clients is professional photos get them bigger and better deals. Many of my clients are professional bloggers, models, and speakers. When they receive clothing items from stores, they believe they continue to book more deals because they give the store professional photos in return. Instead of easily taking an amateur photo on a phone, they take the gig seriously by hiring a professional photographer to take the best photos.
Those that have been in the industry for a long time know how to use their time adequately. For a beginner, it may take an hour to get a few good shots and they may not all turn out well. Or if shot on a phone, you will probably receive a handful of images. A professional on the other hand can easily get over a few hundred frames in just an hour or two.
Always know when shopping around for a photographer, "you get what you pay for". Let me know in the comments what you look for when searching for a professional photographer.