Hi FvM and thx
Yes, it is, or sometimes Brass based as i have just read on the web. i wonder if there is a supplier for those connectors. I mean some way to get already Tapes and Reels of those with some way to use them in automatic placement process.
it is one of the few way to connect pcb on pcb in a surface mount manner. I have seen a castellation way, and bga style connector from autosplice.
Also i wonder if thermal expansion on the daughter card (it is still power conversion) would be dangerous for a surface mount connection.