Why is "Channel to Selection" brighter than same extracted channel?

[ChameleonScales]

As shown below, an extracted channel (here blue) gives a brighter result when using the "Channel to Selection" context menu item and creating a mask from that selection compared to using Colors>Components>Decompose or Color>Components>Extract Component (which both give the correct result):

Original:


Extracted blue channel:


Channel to Selection (on blue):


Is this intended and what is the reason?