I tested on a 15" Macbook Pro 2018 (latest version of keyboard that is softer to type of / less noisy)
Cool to see someone follow through with it. Any streamers out there should figure out a way of avoiding keypress bleed or muting their mics when typing sensitive info (e.g. passwords).
Its not a complicated paper, give it a go.
For this particular open-source hobbyist project, not likely; those who're most likely to attempt to use such a tactic maliciously are likely to keep it to themselves rather than demonstrate that the security concern exists.