Yes adding vinegar to Spinach makes the Spinach taste better.
Also adding vinegar to spinach makes the nutrients in the Spinach easier to digest because of the Vitamin C in Spinach.
Another thing is that when adding vinegar to spinach the vinegar helps to break down or concentrate the digestible iron in spinach.
That makes it more nutritious for your health.
I like to pour a little bit of vinegar onto my spinach so it makes it taste a bit better.
My mom has always put vinegar in with her spinach and it made me eat it better as a kid and I still love vinegar on spinach.
Just don't drink vinegar by itself though as it can cause health issues.