That’s a very good point @kaefert thank you for bringing it up 
I will edit both the Slick and Tiles topics and clarify what I meant.
In the meantime, to answer your question:
Tile and Slick act independently. What I meant to say here:
is that there is no conflict between Tiles and Slick. If you want to use both Tiles and Slick at the same time, you can! You just have to install both of them, separately.
If you install both of the same time, you get something like this in the composer:
And if you use both of them in a topic/post you end up with something like this:
