That is the worst reason to use legendaries, and they are literally not stronger enough for it to matter, people who use lots of legendaries get destroyed in tournaments all the time. The reason it annoys me personally is because they are living legends, you don't just put them in your pocket balls and carry them around for sport. They already have Mew and Giratina, aka Satan, which feels wrong. If you have, for instance, Dialga, who cotrols time, it seems wrong. To carry around a mythic figure that there is only one of Canonically speaking seems weird and pretty disingenuous to whomever you happen to be battling. Their rat or cat or bat against your sun god.
