world size increased unreasonably from applying add-ons

The addition of an add-on (*.mcaddon) dramatically increases the size of the world, sometimes the addition of even just 20 blocks that are part of the installed add-on increases the size of the world by even 1MB. Attached I leave you two targeted screenshots and the add-on.

Steps to Reproduce:

1. add an add-on on a world
2. open the world
3. add some blocks
4. close the world and see if the world size(MB) has changed