Why do they release a bugfix + part of 0.6.3 ? Of course evryone will be disapointed because "not enough content". Just wait and release full 0.6.3. If they promised a release date and felt obligated to release something, then just don't promise anything next time and put out the full thing whenever it's ready.
Keep in mind of the developer(s) providing update once or twice a month, it may be big or small update. Regarding to versions....
x.x.x
[Complete Game].[Major version].[Minor version]
1.0.0 would be consider a complete product
0.1.0 would be consider a major version update
0.0.1 would be consider a minor version update. This can also means bug and patch.
Keep in mind what I explain above is consider a common process of labeling version. It is all up to the vendor/developers to label their version. I have seen some developers start labeling their version update by dates. Which I have done when I would be working on documentation. I would start with [Year][Month][Day] filename. I have done with hours and minutes. There is no right and wrong way for developer(s) to process their version label.
Addition when the developer say the new version is out or coming out, the subscribers and based on the level of their subscription, would be able to get their hand on the early release version of the game. The public would get their within a reasonable time after the subscriber's release. If you are not patience, then join the developer's patreon.
I am a kind of person to wait for the major version update or major version and some minor version. Keep in mind that usually when a major version get release, there are usually some minor bugs that we may not think about or it could be a major issue...