Thank you very much for the information. I was waiting for this update. Electrum would hang during the process of detecting TREZOR T, now it works great.
Do we have any videos of SD-card slot actually being used for something in these phase or is that option just to be future proof for some new coins?
Right now, SD card slot is only used for updating the bootloader. SD card could be used for locally saving labels (right now this stuff is being encrypted on your Dropbox account) and Lightning Network information about your opened channels etc. TREZOR also plans to implement storage which would be encrypted with your private key. However, it will take them some time to release this feature. Let's hope it won't be as "futureproof" as Bluetooth in Ledger Blue which was discontinued.