I have said this before and I say it again. Formal trad kata by itself is a waste of time for any purpose except perfecting formal trad kata. And if that is your goal, fine! Formal trad kata with proper realistic bunkai (not the all too common obvious unrealistic junk) and then drilling it in sparring (as close to free as possible) is very useful -But very few do the first and hardly any of them do the latter. And really, out of that the formal kata is by far the least important part if you want to be able to actually use the stuff against a non-compliant opponent. As a method of skill transmission Kata has failed completely (if it had not we would not have had this discussion over and over again). As it is most who look to kata&bunkai for techniques are usually forced to look to other arts (judo and jujutsu usually as a huge chunk of the skills covered in kata closely resembles skills common there) for explanations and finer points in execution of the skill and stuff found. As a method of cardiovascular training, kata is... ok but not nearly as effective as the alternatives.