Sounds like the usual BS that comes up every once in a while:
- Transformers are for isolation. You can either isolate with transformers or capacitors (X or Y-rated, not just any capacitor). If they are doing capacitor isolation, they may run into some patents on AC and it is nothing new
- Electrolytics are for bulk storage (also needed if you need PF/THD compliance)
- There have been simple switched cap non-isolated supplies over the years.
- 5W / CI is not that high. Perhaps at 0.2W, not at 15W.
- 480V ... so that needs 800V FETs. Let's see how they handle surge (without magnetics).
I am sure they have some interesting technology, but you still have basic physics you have to follow so they are probably being a little optimistic w.r.t. where they can play.