What is the limit to gluing wounds?

Today I had a bit of an unusual case, a 23 year old, infantile autistic with no language and therefore difficult to approach. He had a seizure and a laceration on the eyebrow about 5 cm wide, almost down to the bone, gaping.

The decision was to glue it because he's unable to cooporate to sutures. Which begs the question; can you just glue anything? What are the pros and cons? This laceration would be sutured in anyone else, but apparently if it's not possible to suture without GA you can glue. But I never really understood what the downside to gluing is?

Edit: I need to make it clear that I didn't glue the patient, I called the on-call who handle facial lacerations and I was surprised by their plan.