Copy and paste Messages into Pages does not work, why?

Only the Apple Pages for iOS product team knows the real answer and they do not participate in these public user-supported communities. Applications in iOS and macOS are coded to accept certain data types from the clipboard, but not all data, and if Pages is not written to accept what you have copied from Messages to the clipboard, then that would be as valid a reason as any.

I see picas has made it work… so it must be possible.

Thank you both for providing some clarification. So Cut & Paste joins other unreliable, vanishing, almost mysterious Apple features, like Airdrop and Do Not Disturb. Ciao.

Works great if all text is sent from Notes. eg text in Messages/Pages copy to Notes, text previously pasted in Notes copied from here and pasted in Journal.

In short everything that goes into Notes can be sent and copied to other apps.

It seems like Notes has a cross platform format.

It works for me.