I think there is some confusion here. The point of a VPN is to bridge a device into a LAN, so that internal resources can be (securely) accessed from an external network.
While some companies market VPNs as a kind of security or privacy tool, this is not their intended use at all, and the security benefits are questionable - ultimately you're just sending your network traffic to someone else's LAN, where it gets routed out to their ISP and back to the internet. You can safely ignore these offerings for any corporate use-case.
I think the best way to answer your question is to ask you a different question - if the SaaS offerings are available over the internet (i.e. they're not on a private LAN), do you need a VPN to talk to them?