For a playtrough team, it's not useful in most major battles before Kanto, since it's only good against Chuck's Poliwrath (and maybe Pryce's Seel), and that's it. And while it is useful in Kanto, that is a post game area, you probably will take a long time to get there. Victreebell has solid stats, but obtaining a Leaf Stone is super hard.
Overall, it's is not great, but it isn't completly useless