It hasn't been released yet but it was merged in main and I was trying it out today. I plan dig more into it and write a breakdown. I'm really interested in how it's exactly working to see what corner cases we need to watch out for. As is usual with "magical" features they're great until you run into a corner case.
Probably the best way to think about morphing is as something that gets you up and running really quickly. Then as your app matures you can replace high traffic pages with turbo frames and streams or something else. In a typical app, even when it's mature you might find that 80% of the pages are low enough on the performance requiremetns that you can just morphing and then use the development time savings to really optimise the other 20%.