Neat idea. This probably has the disadvantage of coupling deployment to a service. For example how do you scale up or red/green (you'd need the thing that does this to be aware of the push).
Edit: that thing exists it is uncloud. Just found out!
That said it's a tradeoff. If you are small, have one Hetzner VM and are happy with simplicity (and don't mind building images locally) it is great.
I worked in that area a while back. It is (was then) a quiet part of Sydney just commercial offices and business that supports it. Despite being a fairly central location. It's a beautiful place to hang out you can walk to harbour views.
I thought debugging was table stakes. It isn't always the answer. If a lot is going on logs can be excellent (plus grep or an observability tool)
However debugging is an essential tool in the arsenal. If something is behaving oddly even the best REPL can't match debugging as a dev loop (maybe lisp excepted).
I even miss the ability to move the current execution point back in .NET now I use Go and JS. That is a killer feature. Edit and continue even more so!
Then next level is debugging unit tests. Saved me hours.
I imagine that validation as you go could slow things down though.