@ming.wen It is just a matter of preferences and use cases. A circular form factor uses a lot more space due to the lost part. But I understand it may fit well wearable use cases.
I prefer the 25*58mm Grove Shield for SeeeduinoXIAO and will place an order when they are available.
Adding a SWD connector would be great, as debugging is almost mandatory for advanced projects made possible by such powerful MCU.