A few reasons...
One, it's easier to allow the airplane to naturally crab into the wind down final. Smaller corrections need to be made using this technique (IMHO) in a bigger transport aircraft. It's mass, speed, inertia and higher wing loading make it more stable during gusty or x-wind landings.
Second, using the sideslip method on final tends to block smooth airflow on the downwind jet engine(s) and may result in compressor stalling. This results from the fuselage blocking airflow (more noticable with aft fuselage mounted engines ie..727, DC9 etc)
Third, unnecessary prolong stress on the vertical stabilizer and rudder trying to hold the sideslip. Remember, the airplane wants to naturally crab into the wind...so why not let it.
Lastly, due to the length of the fuselage in large jets, it makes the passengers very uncomfortable when a pilot sideslips on final (not that the boxes I carry now care but back in my commuter flying days...
The sideslip method works well for small aircraft even though I still prefer the kickout method. However, the "kickout" method works best for larger aircraft.
Some bigger jets will land in a crab, such as a DC8 to prevent scraping an outboard engine pod using the kickout method. Those big CFM's don't have alot of ground clearance.