PulseAudio in-/output device confusion

[Petrus de Calguarium]

Adam Williamson wrote:

> Where are you seeing this, exactly? Are you using 
KDE?
> 
Of course I use KDE :-)

I see this in systemsettings/multimedia/device 
preference.

The reason I would like to finally understand this is 
that I have 2 computers (desk- and laptop) and the 
priority of preference is often different, or sometimes 
my laptop tells me that such and such a device does not 
exist and asks whether I would like to remove it, etc. 
Often it tells me that PulseAudio is not working, so it 
will default to PulseAudio Sound Server. Huh? Yes, I 
see that there are 2 entries, but this is all very, 
very confusing and I just want to know what the 
intended order of all these devices is supposed to be, 
from the perspective of someone who wants to use 
PulseAudio correctly to achieve optimal sound without 
glitches and hitches, etc.