Buy if the iPad Pro Isn't a Computer to You
The 2019 MacBook Air and the 12.9-inch iPad Pro with a keyboard are basically the same price. It's clear that Apple is positioning the iPad Pro as a great MacBook Air Alternative, but if you need macOS and a full laptop experience don't jump ship to the iPad Pro.
There are still a lot of tasks that are easier on a MacBook Air than on an iPad Pro. If you think you fit into this ship, don't force yourself into using the iPad Pro as your laptop.
If you are on the fence, use the 14-day return window to test out an iPad Pro or a MacBook Air and see which one fits your needs the best.