In a blog post on his website, Overcast developer Marco Arment explains why he created the clip-sharing feature:
Podcast sharing has been limited to audio and links, but today's social networks are more reliant on images and video, especially Instagram. Podcasts need video clips to be shared more easily today.The new clip-sharing feature can be found in the Share menu, accessed by tapping the share icon in the top-right corner of the player interface.
I've seen some video clips from tools specific to certain podcast networks or hosts, but they were never available to everyone, or for every show. So people mostly just haven't shared podcast clips, understandably, because it has been too hard.
Tapping Share Clip... brings up options to generate an audio clip, or portrait, landscape, or square video, up to a minute long using the current Overcast theme setting. Adding a "Shared with Overcast" badge is optional.
Overcast 2019.4 is available as a free ad-supported app for iPhone and iPad from the App Store. [Direct Link]