Canelo isn't going to know whats hit him. This isn't Chavez Jr, Liam Smith or Amir Khan.
Or Kirkland or Angulo or a shot Cotto.
Fact is, Canelo has been put in with guys he was meant to look good against since losing to Floyd and arguably losing to Lara because it put a dent in his supposed new face of boxing status.
It's true GGG's resume isn't the best either but he has been avoided and was avoided by Canelo himself for a while.
This fight is happening because there's nowhere to run anymore. The demand got too big and Golden Boy ran out of excuses. They have never wanted this fight but people had already started losing respect for Canelo due them vacating belts, going back out of the division etc.. It got to the point where it was better to make the fight and possibly lose rather than keep avoiding it.