Acceleration without gravity

but in puck.js you can use bluetooth and nrf to send data

I don't really understand what you mean here - communications options between Puck.js and Bangle.js should be basically the same.

The NRF.* methods are for bluetooth, and are available on both. Bluetooth.print/etc is still Bluetooth, but is Bluetooth UART.

The Bluetooth UART provides buffering and slightly faster transfer, so I'd say use that if you can