You want to do heavy video and photo editing mobile? Like in a pick up truck or at starbucks? I'm not being facetious, I could legitimately see running through proofs if you're shooting a wedding or on a long excursion trying to capture wild life. I don't see battery lasting long enough in any laptop to do anything substantial though, especially a 4k one. When you compare the ability for a desktop to do these tasks, from a commercial, monetary stand point, the desktops productivity is light years ahead. Time is money!
That said, i think its fine and i don't think you'd gain much performance by spending a lot more money. 1TB HDD is odd on a laptop. Its too much data to have in a device that can be picked up, dropped or destroyed easily. 1TB 2.5" platters are not the fastest either.
12GB of ram is an odd number, not sure how they have it configured.
Overall it should be fine for basic tasks and even advanced tasks - its not slow. But if you depend on this for food i'd reconsider.