The camera will be outside from what I can see, there'll be no breaking and entering required.
A vpn provides better security for the camera at the cost of reduced security for the network at the other end to the tunnel (unless it's set up properly and it's not just assumed that throwing a vpn at it makes everything more secure)
It's all about which site's security is ultimately more valuable.
99.9% of webcam "hacks" are caused by default passwords, and result in people being able to view the camera. The choice world be between taking all possible precautions on the remote site by securing all unused ports, using a non standard application port to evade automatic scans, and having good security credentials to protect that one camera, or create a (small, but new) vulnerability in the home network by having a permanent vpn open to a remote site wuth a network point outside the building that exposes the device running the vpn service.
Each to their own, but I'd rather keep the bigger fish safer, non standard ports with good credentials and an auto password lockout are hardly leaving the front door open with a neon sign inviting undesirables in to shag your Mrs.
The easier option all round would be a small recorder on the remote site that could be vpn'd into when you want to view it, which could then be secured with a password protected certificate the way a vpn should be (certainly one that's being used for secure p2p communication) rather than an automatic router to router link.
Then it depends how secure you want to make it