Lack of complete e2ee is a feature for many large organizations—they still want everything encrypted, they just want a master key to be able to audit communications for compliance/investigations/insider threat identification. They also want strict control over who does what with the app, and where all of the associated data lives. Teams is just a totally different product from WhatsApp in that regard, with all sorts of functionality that will never exist in WhatsApp—tons of control over user identity and access management, integration with all sorts of other security tooling, etc.