Correct. You need not be a part of YPP to use the creator features like custom thumbnails or live streaming. You just need to have a verified account (by phone): https://goo.gl/3iMkBG https://twitter.com/systemcoded/status/953620422284775424 …
We're working on building out separate eligibility criteria for end cards/screens with external links so that channels below the new YPP threshold still have access. We'll share out the criteria once it's ready and won't remove access to the feature before then!
