since this is most likely not a very popular add-on, any browser with it would stand out considerably more relative to not having it.
websites cannot look at the list of your addons. they have to detect the presence of each, which is mostly possible when the addon makes changes to the page content, or replaces browser APIs in certain ways.
Typically its common for browsers that want to reduce fingerprinting (tor, mullvad etc) recommend not installing new addons as then you stand out from crowd.
because if an addon does something that a website can detect, that'll make you stand out
that sounds interesting, but in this idea would those people have to pay for the expenses of the eldely? in my understanding the problem is not that the elderly wouldn't be able to take care for themselves generally, but that they wouldn't be able to pay for things they need or want.