The first message I got from my girlfriend was a response to me sharing some music with her and asking for a song back. She sent a small video of her cat complaining.
If I could have backups of entire conversations, I wouldn’t have to export and save every single video and picture being sent with Signal.
I find text based instant messaging to be shallow and vapid and I have very little interest in them. Texting is best used (for me at least) to coordinate real life plans (I'll be in front of X at Y o'clock) or quick task-oriented notes (Hey babe, can you grab some sliced turkey if you're still at the store). If you want to actually talk to me, call me or let's meet in person.
This attachment to one's messaging archive is IMO a symptom of data hoarding. 99.9% of text conversations won't be interesting in the future because they weren't interesting when they were happening.
That said I do like enjoy the feature where all of the photos from a given conversation are easily accessible.