Their offering strikes a decent balance between the two. The fact that it is a native application really helped me when I traveled internationally, where my connection was spotty at best. I had a minimal slow connection on my phone that I couldn’t tether, and otherwise, I had to offload periodically where Wi-Fi was available from my PC. In places where you can assume to have a strong, always-on connection, they don’t make much difference, but in situations where I can’t count on it, Microsoft’s structure, which can tolerate offline usage, is very useful.