I did better once I nailed down how to use my tablet and I had been a mouse user for quite some time with a top of the line G700. I don't know if "easier" is the best word but you make less wasteful movements and spend less energy. Which helps you concentrate more on the game.
Although playing with a mouse was nice, some movements are just really awkward with a mouse. Most beatmaps are basically as simple as drawing a continuous line, something that's pretty hard with a mouse. I mean it's simple, can you draw a line very quickly with a mouse with really good accuracy? Maybe not. Can you do the same with a pencil? You may not be able to do that either, but it doesn't have as steep of a learning curve.
Pretend to have the same skill with a tablet and a mouse. Play a song on hard/insane. Tablet will surely wins for jumps, but mouse will surely wins for streams. It depends on the map. But in most cases yes, it's easier with a tablet.