Recently I connected Dynamics/CDS App for Outlook form Appsource to a model-driven power app to track e-mails against the account and contact base.

The integration worked but with a few differences compared to running it against a dynamics 365 sales instance.

1. Activity roll-up to parent account is missing
In a model-driven app, activites related to a contact are not beeing rolled-up to the parent account timeline. So when you open an account in a model-driven app you cannot see the activites of the connected contacts in the activity timeline. You would have to click through all the contacts one by one to see what's going on.

2. Show tracked email on all related contacts is missing
In Dynamics, when you track an Email. The Email will show up in the activity timline of all contacts referenced in the Emails "To" and "From" fields. In model-driven apps the activity does not show up on contacts referenced in "To" and "From" but only on the record referenced in the regarding field. Without including the activity party fields, you can only make the Email visible in one place, the regarding record. This is limiting because you usualy want an Email related to one or several persons and a topic (D365 -> Opportunity, Model-driven app -> any custom entity).

Please include activity rollup and the visibility of activities from activity party fields possible in Model-driven app.