Davo, me thinks mostly for those that have little idea about PJ's and what they can provide, but not having seen one of the new breeds its hard to judge and as you say will have a use in some situations.
You'll find HDM Fibre cable is thin, as is the plug to install in a wall/ceiling.
The item is a HDMI switcher not a splitter. These switchers amplify as well.
It will be fine using short 28awg "high speed" cables