Is that a good practice to use primitives placeholders in 3D?

I have begin to work on a game prototype and I have this question : is that a good practice to use primitives placeholders like a capsule for the player and cubes for enemies in 3D for the prototype?

Because in every tutorial that I've seen, they always use 3D models that are ready to use. So could this cause some problems like with performence or other things when I'll replace them with real models? Or is that the best solution to create fast at the beginning?

Thank you!