Eh. At that price I think the Pro is a good choice but the Air isn't really much slower than that Pro in stock config. But you do get a nicer screen and speakers at the expense of Touch ID and keyboard.
Hope you like it. I absolutely adored the 13". If it played TF2 better I'd have stuck with it versus being inane and spending so much on the 15". I think you'll be astounded how nice it is coming from an Air.
I gave a 2017 Air to my lady friend after realizing I could never go back to the old style laptops. That 13" Pro definitely feels like it fills that roll. I wouldn't be surprised if it disappears off of retail channels soon. It's too close to the new Air.
I wouldn’t be surprised either. As you said the 2018 Air and 2017 nTB MBP are really similar. I got a nTB I’m 2016 instead of an Air and I think if I were to buy today I’d still go with the MBP. The only thing the Air has that I’d really like is a Touch ID but I’d rather have the screen and extra processing power of the MBP.