Before revision:  On the other hand, pure character-level models, though robust to misspellings,  often lead to unreasonably large sequence lengths and make it harder for the model to learn meaningful contiguous characters.
After revision:  On the other hand, pure character-level models, though robust to misspellings, pure character-level models often lead to unreasonably large sequence lengths and make it harder for the model to learn meaningful contiguous characters.