There has to be a streak function. It is a motivation to listen podcast every day. A virtuous cycle continues…
What is streak in this context? 
I guess how long since there was a day nothing has been listened.
But yeah I agree it’s going to be difficult to really define it because some would say a day doesn’t count if you didn’t listen more than x minutes or at least one episode…
I cannot imagine going a day without listening to several podcasts! 
Though I appreciate the thought, if you aren’t eager to listen to podcasts every day, you’re subscribed to the wrong podcasts.
It is a bit like those users who seem more interested in getting their listening stats up as if it is a challenge to be top dog rather than to be interested in listening to the podcast content.
A web site I visit several times a week has started logging streaks for how many consecutive days people visit. It keeps a tally on the page, and also sends an email when I hit a milestone like 5 consecutive days, 10, etc.
The funny thing is that the email tells me what a big accomplishment it is, and then says it’s not a big deal if I miss a day because I can start over and reach even higher heights. After laughing at the mixed messages, I inevitably mumble something like “What do I get for those streaks?”
you get a social media addiction 
Ah yes, there’s that