Why use BTC? They don't! The sheep just hold it, hoping to get rich on price, which is not what BTC was designed to be (a currency). When a new pyramid scheme comes along, they won't hold BTC any more, they'll move it across while continuing to use normal fiat as currency. They don't care that Monero, LTC or even Zaps are better currencies than BTC, they jumped on board a get rich quick scheme.
Discussion
..and your response to the second question?
Are you being funny? I asked you 3 questions some posts ago here and didn't get an answer to any of them: https://primal.net/e/nevent1qvzqqqqqqypzp68wr4wwu4hs49xxjxyh5n725hmqdfhgqhkau0rujn0qw0uncqujqyg8wumn8ghj7mn0wd68ytnddakj7qg3waehxw309ahx7um5wgh8w6twv5hsz9nhwden5te0dehhxarjv4kxjar9wvhx7un89uqzp5lz5wgy7gsp9wq9kmahwv6hxjcrldqthqfn02rrjc3ee4r4l6adzqw2f9
To answer your second question, the only thing I can think that BTC offers people at this stage is a get rich quick scheme. And even that is wrong, because there are coins more undervalued and less inflated in price. BTC certainly doesn't offer the best currency transactions.