The best reasons are:
No physical currency involve!
I don't think so because we need physical currency to purchase bitcoin in the first place, and now there are a lot of places in some countries that doesn't have any merchants which accepted bitcoin yet, then people in there need to convert bitcoin into physical currency again. So, physical currency still involve imho. In my opinion, the best of bitcoin is you can send/receive (transactions) it wherever you want without any restriction or borders with low fees and as easier as sending an email (faster).
We can consider it faster than remittances but if we compare the other payment methods online bitcoin is not the faster or fastest. bitcoin still relaying in your fee and the transaction size.. for me the good thing that i want in bitcoin is the anonymous transaction also you can gamble without restriction giving your real identity before you can start to gamble unlike in paypal that you need to verify it first before you can fully use it and i think it takes 20 days or 60 days your paypal account before stablish that you can use for buying online.. unlike bitcoin that you can use it after you create.