Amazing project and glad to see something like this exits. While my current setup dosnt allow for this, if that ever changes and I start taking more latex notes I will be ordering one of these.
The killer feature of Mathpad is not LaTeX (although that is supported) - it's letting you directly type mathematical Unicode symbols practically anywhere you can type regular text.
Mathpad will remain available on Crowd Supply long after the campaign ends (albeit at a higher price), so just come back later when you need one!