It all depends on what kind of video you're working with and how often.
If it's occasional 1080p video editing, the 2018 MBA will do the job, no problem. Photoshop is also fine, unless you're using crazy large/heavy files, in which case you already know you need a high-end laptop.
If it's occasional 4K video editing or you're working with very short videos regularly, it'll do it, just a bit slowly when it comes to rendering/compressing. It's about half as fast as a current Pro for this kind of work, but if it's just a couple times a week, the difference between 10 minutes and 20 won't change your life.
If you're doing 4K video editing regularly, the Pro is the only sane choice, and even then you really want a 15" with the high-end GPU or a desktop, because even moderate 4K video editing will suck down all the cycles you throw at it and still be frustratingly slow, unless you have workstation-level power.
Long story short, if it's mostly a web/office/mail machine that needs to do a bit of video/photoshop on the side, the MBA is a fine choice. If you're looking for a machine that will be doing video work more than a couple hours a week, you'll want the Pro for sure.
