This functionality, when it is widely available, solves the slowest and hardest part of the magic that DOM diffing libraries like morphdom provide.
Much is being made of how it will impact client libraries in other threads, but it's actually driving changes from the server which is most helped by this seemingly simple feature.
To make this real, imagine that you are connected to a collaborative (realtime multi-user) app and someone else drags to reorder an item in a list. Let's say that item has a text box that you're typing into. In today's browsers, all but the most clever implementations will clobber your changes. When this drops, the item you're typing into should be able to be programmatically moved to a different location in the DOM and you won't even lose focus.
That's a big freaking deal that makes server-rendered systems like StimulusReflex, LiveView, Hotwire and HTMX even more desirable options compared to SPAs.
Much is being made of how it will impact client libraries in other threads, but it's actually driving changes from the server which is most helped by this seemingly simple feature.
To make this real, imagine that you are connected to a collaborative (realtime multi-user) app and someone else drags to reorder an item in a list. Let's say that item has a text box that you're typing into. In today's browsers, all but the most clever implementations will clobber your changes. When this drops, the item you're typing into should be able to be programmatically moved to a different location in the DOM and you won't even lose focus.
That's a big freaking deal that makes server-rendered systems like StimulusReflex, LiveView, Hotwire and HTMX even more desirable options compared to SPAs.