Doesn't need to be an overly complex application but a video and article series how-to would be a capstone for this project to kickstart and maintain adoption of this SDK.

Zero modifications to the demo app I can get Scan card to work but the Sign button doesn't pull anything up. Nothing in the logs either 🤔

Demos should be more fully fleshed out. The cordova one doesn't even have a README atm and the capacitor one is using the serve command which will open the app in the browser which won't work with the signing cards so physical device usage should be enforced.

Building the tech is really only 35% of our job as engineers. Documentation and marketing is the other 65%.

Either in the README, the Wiki or an examples directory. This is an amazing combo of software/hardware but for developers to really "get it" they'll need a little more help to go off of to kickstart their own instances.

Stellar has a SEP for multikey derivation and if possible I'd love to see this feature supported on Tangem.

https://github.com/stellar/stellar-protocol/blob/master/ecosystem/sep-0005.md

Primary impetus is allowing for a separation of interests through a multi key wallet. A single wallet is a single point of failure and usage which in many cases will be an unacceptable limitation. Multisig solutions, hot vs cold wallets are all stunted if a single wallet === a single wallet key.
My personal conviction is crypto wallet keys should be treated more like passwords than credit cards. Unique keys for each use. So same device with many keys for many uses becomes pretty essential to support this. The only alternative is to hold a dozen or more physical keys, which to me is a step backwards.