I think this workflow sounds good however as is often the case it is common to leave out a way to submit a delete or merge (tiddler) through the inbox. Such methods should be implemented from the begining rather than added later.
Similarly the idea that something more complex can be submitted such that once injested into the tiddlywiki it may trigger actions or renders inside the interactive wiki is well worth thinking about when architecting such a solution.
- I know that you @pmario are security aware, so allowing a key to be provided that must match one in the wiki etc… can be considered, however such automation is usualy taking place in a trusted environment.
[Edited]
See Proposal: WikiShell / TiddlyCLI - A Command Console for TiddlyWiki - #38 by TW_Tones and my references to using bookmarklets. This introduces another mechanisium for Intergration and Automation by triggering JS Functions.