Use of apps such as Blitz and Zack

Hi all, I been watching a fair bit of league content and have seen a lot of promotion for Blitz and Zack, which are apps that import builds and runes etc from directly into their client which i have been using and finding it really helpful when trying to learn new champions. I heard from a friend however that they got banned for using a third party app when Blitz was the only thing they were using, so are these apps frowned upon by Riot or was this person wrongfully banned? I don't want to get the same issue myself and will happily stop using it if it is frowned upon.
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