@Siegfried67This game is meant to reflect real life. The tensile strength listed on the package is the reliable test strength of the line being sold. It does not mean that the line isn't capable of holding a bit more. It really is not as much an 'improvement in performance' as it it is more of it will last a bit longer in the red than a lower quality line. However, that is what gets some people into trouble. You see, while it is enduring that enhanced strain - the entire setup is enduring that. So for example if you were using high quality line very close to the capacity of a telestick and the telestick was lower quality there is the chance that enough force would be applied to the rod to break it before the line broke.
Also different types of line behave differently. Braid does not have any 'stretch' in it, whereas mono is quite 'stretchy', and flouro has a little stretch. Part of the game design is exploration. There are many things that are not shown explicitly to the player as the player is meant to explore and experiment.
Here is a good article on the real life applications of the various line types: http://guide.sportsmansguide.com/tips/braid-vs-fluorocarbon-vs-monofilament/ It is a North American focused article, but should get you started.