Originally donations to matrix.org foundation were supposed to be used to fund matrix protocol work and to hire a developer. This is still listed as a goal (that was reached) on Patreon. Only due to asking I found out that this never happened and donations are used to pay matrix.org homeserver instead, which of course is also a good cause, but should be communicated transparently.
I don't mind the accounts specifically, I just think that making them public is the easiest way to fulfill the needs of transparency. Of course a summary on the website, a blog post with explanations, etc, would also be nice, but I understand those mean extra work and there might be more important things the prioritize.