Well, the truth is, you may not want a studio photographer. If you want that very popular "Golden Hour in the fields" look to your photos, then a studio photographer will not be a good fit for you. But, there are complications with an outside photo shoot that aren't an issue for a studio photographer.
In a studio, it doesn't matter what time of day or evening it is because I don't depend on the light from the sun. I could schedule a shoot at 8 o'clock at night and the photos will still look like you're sitting next to a window on a bright beautiful day. I also don't have to worry about that harsh 12 noon light that can cast shadows all over the face. My light is always soft and beautiful, which is very flattering for every one.
Weather is another factor that has to be taken into consideration when you choose an outdoor photographer. Here in the Midwest, the weather really does change every 5 minutes! It's not just a line in the movies. There is a very low chance of rescheduled appointments due to weather when you decide to book with a studio photographer.
Finally, and my personal favorite reason, I can control the light. I can create a stunning image in my studio that wouldn't be possible outside. I have studied light for tens of thousands of hours and I can adjust the light so it is perfect for you. You just have to trust your photographer. Review their portfolio and make sure the style they produce is something you are drawn to.