Despite not having services for users, some other potential justifications for a VPN would be:
- Network and admin teams access to L2/L3 devices like switches and routers
- RDP access to workstations
Besides those, if you're not actually hosting any services on an internal network for users to VPN in for, then no there is no reason to have a VPN. In fact, doing so would simply result in +1 more port (1194 for OpenVPN for example) being open on your perimeter, and therefore to the public. This would, albeit mostly negligible, increase the attack surface of your company, but with nothing to gain, because you'd have an extra port just sitting open.
If you are talking about accessing outside resources like other corporate networks or simply browsing the internet, doing so over a VPN offers several benefits in terms of security and privacy. As user vidarlo pointed out, the benefits in this case would reduce the chance of MiTM attacks, and also provide traffic inspection for roaming devices. To add to that, you would also have better privacy since your actual public ip would be replaced with one from the VPN provider, thereby shrouding your true public ip to the sites you visit.