Hi and welcome!
If the H is small, then observation is appropriate. You can't assume that it is going to get large, you can't predict how large, etc. Their point of view is that intervention may be unnecessary and they don't want to intervene unless it's needed.
Many, many hemangiomas don't need treatment at all. If or when it does start to grow alarmingly large and fast, then you can discuss other options, I think.