What is your experience with Blockstream Jade?

Hey, I find the Jade to be a really good device on paper for the price, but I wanted to hear some opinions from you all.

Can you use it as a signing device without ever using the Blockstream Green app?

How does it compare security wise to a coldcard?

Is it possible to go fully airgapped if you need to usb connect it to a PC to update its firmware?

Thanks!