Hi -- I'm one of the two Pindigo devs.
I've noticed users posting 0 point scores to Pindigo as a way to track that they've played a machine but they may not have a photo or record of the actual score. That may work for you.
We'd definitely like to integrate with Pinside again in the future, but there's only so much we can do at once. Once we get v4 fully released (it's out for Android now -- iOS coming soon) then we'll get back into the groove of asking our patreon supporters (https://www.patreon.com/pindigo) which feature we should work on next. I'll be sure to add pinside integration to our next feature polls.