Frequently you don’t need to connect it in to your canvas app because these are used by different roles and for different purposes. Think of a sales person vs a sales manager. Sales person needs to see customer information and create or update opportunities, vs a sales manager needs to manage a team of 15 people. Salesperson uses canvas, sales manager uses mode driven.
Look at it this way—if someone say “I need to do __________” then a canvas app usually works. If they say “I need to manage my _____________ process,” they probably need a model driven app.
another area that is much easier with mode driven is data validation—since it has tools like advanced find and more data dense views, if I have a canvas app that has either a migration or integration from another system, without a model driven app it is extremely difficult to validate the data and relationships are being created correctly.
Take a look at Microsoft’s hospital emergency response solution. https://powerapps.microsoft.com/en-us/blog/emergency-response-solution-a-microsoft-power-platform-solution-for-healthcare-emergency-response/
it is a great illustration of this—for the frontline worker at a single hospital who is counting the beds, discharges, patients, and ppe a canvas app is an awesome solution, but for the person at corporate who is creating new facilities and managing the entire process, including moving equipment between facilities, the more data dense interface for model driven apps is the better experience
