This will allow you to notably mitigate the drawback of drawing an extra content of a Planeswalker by playing that copy to, in effect, refresh the loyalty of a Planeswalker or to get an additional enters-the-battlefield trigger on a famous permanent.
Listed here is the rule covering Legendary permanents:
704.5k If a player controls two or more legendary permanents with similar title, that player decides one of these, plus the rest are placed to their proprietors’ graveyards. This is called the “legend rule.”
Observe that to allow the Legendary state-based activity is triggered, the Legendary permanents tend to be both currently in the battlefield and as a consequence any triggered enters the battlefield capabilities (ETB) may also be triggered. As the Legend guideline is a state-based activity, the choice of which Legendary permanent are going to be kept are created before the ETB caused abilities are positioned on the bunch and resolve.