why expo stores js bundle in an URL

I want to create a production .ipa file for an enterprise. I don’t want any OTA update for my app. So I configured app.json accordingly.

A.) When I simply run expo build:ios all my static files will be stored in expo CDN. And manifest.json file inside the .IPA file contains imageURL, assetURL, bundleURL pointing to Amazon CDN.

Because of privacy issue I have not used this case (A.)

B.) Hosting on own server:
i. expo export --public-url .
ii. expo build:ios --public-url <path-to-ios-index.json>

In this case (B.) all my static files are hosted in my own server and also bundled inside .ipa file. Here manifest.json file inside the .IPA file contains imageURL, assetURL, bundleURL pointing to my server endpoint.

My question is I have disabled OTA updates. Then What is the necessary to host the static files in an URL in case (B.)