]

I never said it was the same. I said the anonymity uses the same underlying approach as cryptonote so the resulting anonymity is the same (or worse, if minting/destroy is used too much, but that is up to the users I suppose). I acknowledged some minor differences, but I don't believe they are particularly significant in the area of anonymity.

As for why thousands of hours were spent on it, you would have to ask them. Presumably they thought that reimplementing it all was a good idea for whatever collection of reasons. I guess the market will decide.