PornPen (pornpen.art) review
PornPen uses tags to generate images and offers an editor for selected regions of an existing result. Its terms put reuse rights and attribution alongside the choice of generation mode.
Private Mode changes what you can do with the output
The terms describe watermark-free images in Private Mode for Pro users, with rights assigned to the user for personal or commercial use subject to the agreement. For Free and other non-private images, the terms require attribution for sharing and written consent from the service for commercial use.
Comparing rights before you publish
PromptChan says its public mode gives the service and other users rights to reuse creations. Its private-mode rule leaves them outside public and commercial use by the service. PornPen similarly makes mode important, and gives a specific attribution rule for non-private work. Choose the mode before you start a project you intend to share.
Anabel’s take
I'd use the tag editor for a fictional composition I expect to revise in small steps. If I planned to publish the finished work, I'd choose the mode with terms that cover that use before generating it.