Usability
Interface 
User-friendliness/complexity of the tool´s interface
Intuitive, easy-to-use.
Time efficiency Time needed for mastering the „how-to“ of the tool and a production of a task
High.
Interface language(s) The number of languages in which the tool is currently available/adaptable to
Dozens of languages, among which Norwegian, Occitan, Swedish, Kabylian, Arabic, Punjabi, or Indonesian.
Respect for privacy Does the tool require registration? Who can see my data? Can I remain anonymous?
Medium. Excalidraw collects personal data and shares it with third parties, including for different purposes, including advertising. However, users can opt out of targeted advertising cookies. Excalidraw’s highlight user consent as the basis for operating user data. It also outlines different security measures in place. It seemingly complies with the GDPR since it mentions observing EU’s privacy laws, but this is not explicitly stated. See more here.
Saving work for future use Possiblity to save your or others´ work for reuse/reproduction
Yes. Users can save and export data from Excalidraw.
Tailorability (If so, how?) Possibility of the tool to be used for a range of different activities (e.g. to what extent you can organize a project assignment with a central activity based on this tool)
Yes. All changes are made by users.