I use Zwift primarily in the winter, when it is raining or when it is very hot. But when possible, I still prefer to ride outside. My suggestion is to create an option so that the outside road miles and climbs I do can be transferred to Zwift. I use a bike computer (a Garmin Edge 1000) so that my claimed accomplishments have been recorded. I would like the Zwift team to create a link to transfer my rides from the Garmin (& other similar devices) to Zwift.
I don’t think this will ever happen since Zwift wants you to earn Zwift XP while using Zwift and I really don’t think they will allow uploads of non Zwift rides into their system.
There’s already a request for this:
I’d suggest voting for that and continuing the conversation in that thread.