If port forwarding is a premium service on OP's side, then this is a clever workaround for it. However, my recollection is that by having UPnP enabled ends up being a security risk considering that you are basically allowing anything within your device to open ports directly into your firewall. If you end up having malware on it, then it can quickly spread to the remaining (vulnerable) devices in the network.

Note that I haven't messed around with UPnP for ages, perhaps the protocol developed more since last time I tinkered with it...