If all you need is Photoshop, that's true. But, IME, nothing steps to Premiere and After Effects, particularly in combination. And modern Premiere is worth paying for, for performance if nothing else. Going back to the scary old days of stuff like Voukoder--no thank you.
It's not Premiere. That might sound flip, but Premiere is a learned skill and I have yet to discover really compelling reasons beyond price (which isn't actually that expensive) to use Not Premiere. From a feature perspective its workflow options are sub-par; for example, it doesn't directly interface with After Effects. AE Live Templates in Premiere alone has saved me hours of time rendering out of After Effects. And AE, too, is not optional; while I like AE a lot less than I do Premiere, it sticks because--and there's a theme here--nothing else really does what After Effects does while integrating into an NLE. The ecosystem matters.
I think Resolve is fine if you don't know other tools or your needs are small. I've used it in a pinch before when I didn't have any other options, it's totally usable. And there are some tools (grading, obviously) which are absolutely top notch, and if you are in an all-Blackmagic recording stack I can definitely see some benefits to ease-of-use when, say, pulling video recorded from an ATEM Mini and some Blackmagic cameras. But it's a limited editor with limited compatibility with everything else in my workflow and those of the folks I know.
(No, definitely not Resolve.)