I won't encourage its use, i will just say that it is a situational check, because it is. Also Night Slash is the main slash on the set, and if Lando-T comes in on anything else other than Ice Shard it basically forces out Weavile (it doesn't even need to stay in and lose 50% of its health as anything can handle a -1 Weavile). Not to mention that most of the time it is pretty easy to see if Ice Shard is coming. For example, if the opponent has Jellicent or defensive Starmie in, i can switch to Lando-T with relatively little risk if i predict the opponent not using Pursuit and using Night Slash. And all in all, Lando-T is a check to Weavile (going by the meaning of the word check) and for this reason alone should be mentioned.