I agree, I would not "mix" regular lines and Q-Power lines.
Maybe it will be fine, but its just that the Q lines are so hard and strong in the coating, that they might be hard on the sleeved normal line ends.
In general - Q lines are much stronger regarding "wear".
So if you are a smuck with your lines, and often pulling them through lots of bushes and sharp rocks and shells etc etc - then Q lines is the only solution IMO
On the other hand - with "normal" care, lines today hardly ever seem to wear out...
I've linesets 3-4 years old, and hardly any signs of wear (and I have +150 sessions per year).
So lines today last almost forever, unless you have bad luck of course, where a line can get damaged or snap from day to day.
I stopped using Q lines, as they were a
hazzle to roll out, so logging so many days on the water, they became a no no for me.
BUT, they are soooo easy to handle, as you just need some plain Q power line in sufficient length, and now you dont need to sleeve or do anything - you can just tie knots and loops ANY time whereever you want - thus easy to make any line length or extensions "in a jiffy" on the spot if you want to.
So no, they dont come with loops or knots, just plain line