BTC Transaction Cost decreasing because:
Support for the Bitcoin scalability upgrade Segregated Witness (SegWit), which is designed to make transaction fees slower and transactions times faster on the Bitcoin network, was added to the latest Bitcoin Core client version released on Feb. 15, 2018. SegWit support was also added to major exchange Bitfinex today, Feb. 21, and scheduled to be released on the exchange and wallet platform Coinbase by mid-next week.