Items will never be used in big tourneys (well maybe special ones, but not in real competitive ones) simply because it's based on luck and less skill. Like say someone was at 50% and the other at 150%. A hammer pops up and the 150% picks it up and wins a match. The 50% guy had no chance. With no items, it will be purely based on skill.
But don't get me wrong, i'm not against items. They're fun to play with but in competitive gaming, the toys should be put away. Like in counter strike clan match, would you like it if you were about to get a headshot on someone but he suddenly transformed into a tank and was able to blow everyone to smithereens? (much like the landmaster) Ignore the exaggerations but I just wanted to illustrate my point.
I will be definitely using items when playing with friends but I will not be using them when practicing for tourneys.