I get people arguing the security risks but there are plenty of other apps avaialble for download with a security risk in place and nobody complains about this.
Furthermore I think if it's wisely implemented it should be pretty secure, I.E. No Flash, Java or any other plugs, just a basic web-browser which by default is restricted to LAN Access Only!
This way you can acceess any sites you have on your LAN but nothing more, on that basis if you manage to hit an infection, well you were already impending doom anyway as it came from your LAN, there is an argument for giving people the option to access WAN from it if enabled too but I personally can't see any good use for it.
People suggest reverse proxies, port forwarding etc. which in some cases is almost certainly the right way to go about it, but in my view you want the least WAN facing Open Ports as possible, so if that can be reduced to 1 point of entry through the DSM Login behind your Certificate with a decent password I don't think there is much more you can do, unless you want to go VPN or SSH Route but as people have discussed this is not always practicle!
So yes +1