I have never tried using the Convert to HBD or HIVE option. I'm glad I was taught how to convert between the two by buying and selling in the internal market. It's true that waiting for 3.5 days is quite long when the amount of HIVE you're trying to get is not that big. I think the Convert option is more appropriate for bulk conversions since buying or selling huge amounts of HIVE or HBD takes a long time (maybe longer than 3.5 days) because of waiting for prices to match if you're trading in the internal market.