B: Apps are great sharing method for multiple environment, and best way of sharing for users in production environment.
Power BI App is the solution for multiple environment approach. With Power BI App, your development environment (workspace), and user environment (App) are isolated from each other.
Note: If you are using SharePoint online as a portal for document management and some other reasons already, then consider using Embed in SharePoint Online feature of Power BI reports. This method is secure and you can share the report only with Power BI users you want.
E: Sometimes, you don't need a secure way of sharing, you may search for an easy and free way of sharing, and your content is not confidential or sensitive. Publish to web is your friend in such situation. This is the only free way of sharing in Power BI, but be aware that this method is not secure.
Publish to web method, gives you an embed code, which you can use in any web pages to embed the Power BI report in it
Reference:
https://radacad.com/power-bi-sharing-methods-comparison-all-in-one-review