What are you talking about?

A MacBook is optimized for a larger screen and comes with a better keyboard and trackpad.

I use both my MacBook and iPad all the time, because their hardware form factors are better for different things.

I don't want to read books on my MacBook and I don't want to do development or writing on my iPad.

I briefly tried using my iPad as a Mac through the screen sharing. It's not as useful as you are imagining.