Does it matter how far I walk each day?

Does someone who walks the suggested 8kms per day have the same experience as someone who walks 5 kms per day.

The reality is that everybody does the virtual Camino differently.
Any numbers we give are just guidelines to estimate how long it will take you to finish. What you actually do is entirely up to you in exactly the same way it is on the Camino.
There is a common saying... "it's your Camino". Which means it is entirely up to you how you progress.
Having said that, what has been reported back to us from our virtual pilgrims is that progressing along the Camino Frances virtually puts them in a 'Camino state of mind' which tends to be similar to a state of mindfulness where they are honouring their walking efforts with self reflection.
Some people are so busy with work that they are logging the distance they do in their daily lives onto the app and it has changed the way they think about all the running around they do for work as they are doing it through the lens of a pilgrim.
Of course the health benefits of regular daily exercise are well documented. However, the benefits of regular time each day to reflect on life as a pilgrimage, from what people have been telling us, is independent of the actual distance walked each day.