The two can be used together and also you’ll often customize a theme which has a page builder but there are dissimilarities. https://www.evernote.com/shard/s667/sh/76def5fb-a10f-fc71-dca2-e8e4c03f57c0/ALm6OPKz0hXaqsna9liFE-ftQC_erijpkpWXO_R0s7EgyTLP-wARq54GjQ