Different people have different expectation and requirements. UE4 is a very flexible engine with lots of configurability so it can run on anything from a low-end tablet to a high-end pc.
I do a lot of C++ development, so I want very fast compile times. I’m also on a deadline, so time spent waiting for my computer costs me. So I’ve spent the money to get the computer I need to do my work.
If you’re on a budget and just want it for learning, a low-end machine like yours is perfectly acceptable. You’re going to spend most of your time starting out reading docs and watch videos, then in the engine, so it’s not critical how fast things happen.