man, you have a thousand questions 
- Is it the blue line showing in the anomalies badge is that what the vm or host is using at a specific time right? -> not sure that I understand the question
- The values that are displayed in the anomalies badge, how long did they be preserved? -> you mean the symptoms on the right pane?
They will be shown while they're still considered active. So they'll most likely go away soon
- And when did the value for the anomalies badge change with the knowledge about the different values of datastore, disk, cpu etc.? -> because for them there is also 'dynamic range' being
calculated. And they went off. And because they "went off", the anomalies badge went > 0. Consider it as a summary, that for this VM something anomalous (out of the ordinary) is happening.
See snapshot 
- And what is if there is no blue line? Is it then using 100%? That could not be right? -> look at my picture. The blue thing is not a line, it's a range - from A to B.
It is telling you that for the past month, for most of the time, that metric moved only inside that range. e.g. in the case of CPU, was between 0 and 15% usage.
And right now it's outside that range, which is an anomaly (something different from the normal behaviour)