Effect of temperature on cooking
(Note that I'm a rather bad cook, except in the lab!)


  Is there any sense to extracting the pears from the liquid?


Yes! Yomen Atassi has already explained that you actually have to consider two (distinct) processes in the recipe:


Cooking the pears for a short period of will yield the right consistency. Additionally, some transformations happening during the cooking will possible break up some cells, convert some ingredients to even more tasty ones, and maybe even facilitate the later take up of other of other compounds from the liquid. If you cook for too long, the pears will be sludge.
Marinating means that the compounds dissolved in the liquid will permeate the pear and add to the taste. Imagine that the pear acts like a spongue and sucks all the good stuff in from the marinade. This needs time.


With a two-step procedure given in the recipe, you should get the best of both worlds and I hope that the dessert was really tasty.