Yes, this seems like a prudent choice for companies to use Facebook, excuse me, "Workplace", to manage internal data. Heck, why does Facebook need to sell ads, they could just sell "Workplace". The service seems to be working well for Facebook, except for the leaks.
Workplace (the product) has nothing to do with this but it's the policy of Facebook (the company) to trust their employees to use any information responsibly to do their jobs (with the exception of user or HR data).
Those claims about privacy and security are certainly believable. Facebook has only leaked a billion or so profiles. https://en.wikipedia.org/wiki/Facebook#Breaches
Yes, this seems like a prudent choice for companies to use Facebook, excuse me, "Workplace", to manage internal data. Heck, why does Facebook need to sell ads, they could just sell "Workplace". The service seems to be working well for Facebook, except for the leaks.