Hey there!
Thanks for supporting us, and I'm sorry to hear about your disappointing experience.
To clarify, currently neither client offers this functionality.
Our long-term goal is to continue to have multiple game clients available for people to choose between, and for those clients to enjoy feature parity wherever possible. In context of Cloud Save, that will probably mean us creating our own proprietary solution at some point, and ensuring that it works for all clients across all supported Operating Systems.
With that in mind, we have a choice to make in the short-term. Adopting support for the Steam Cloud using Valve's API would be less work, and so it would be quicker and easier to do. However it would also mean that the standalone client doesn't have this feature, and so anyone wanting to avail of it who uses that client would need to link their accounts and download the game again. Additionally, it would also mean more work overall - we'd need to one day migrate save data from the Steam Cloud to our own equivalent.
Another thing on our minds is that we are expecting the number of people requesting Cloud Save support for locally stored characters to fall off substantially once server-side, online-only characters are made available. On balance, that's probably an argument of getting something available as soon as possible and rolling our own solution at or even after release.
There's a good chance that we will end up going with Steam's functionality in the short-term and providing a guide on how people not currently playing through Steam can claim the game on Steam and begin playing there. I'm not sure what the idealist of me thinks about that, but this might be one of those 'Don't Let the Perfect Be the Enemy of the Good' scenarios.
As always, we do this work for you folks, so we'd love to hear what you think. 😃