I was also shocked, and immediately set it to private. I registered using an email address (as I do for practically every online service I use) so I don't have to deal with the Facebook dimension.

However, for the handful of people I regularly send money to, I can see all of their transactions on the home screen, including business fees (which reveals the freelance rates they charge), family loans, etc. I take it they have not limited their transactions to "private".

Regardless, I am amazed that Venmo/PayPal thought sharing payment activity would be a good idea.