I think this one (global-props) gets serialized as JSON once you interact with and save it, rather than eagerly on upgrade. This is true in 8.1 as well.
Vision Client tags are just suffering from gross neglect.
The global props resource is still stored as binary in 8.3 (technically, it's gzipped XML, so in theory a smart enough git hook could possibly edit it?), but it's relatively high on the list of things to migrate to a human readable config. Possibly as soon as some early 8.3 release.
The big highlight feature of 8.3 is that all gateway configuration moved from the internal database to the filesystem, and (at least the vast majority of) that config is now stored in simple human/machine editable JSON. Project configuration is a lot more complex by nature and has to be tackled one resource type at a time; the only significant change for projects from 8.1 -> 8.3 is in gateway/session/client events, which can be manually migrated in the designer into individual human readable files.
Vision client tags (and a couple of other Vision resource types) are also slated to be moved to a human readable format, eventually, but it's not a particularly high priority as we try to avoid changes to Vision that could introduce risk.
: How to deal with .bin files while using git? - #2 by pturmel