How important is it that the price of BTC is stable for extended periods, in order for BTC to be widely adopted and what are possible solutions to stabilize the volatility?

Also, I believe BitPay and CoinBase remove this volatility for merchants by exchanging the BTC soon after a transaction is processed, does this not defeat the purpose of BTC? As such, the merchant should use the received BTC within their supple chain, but this can only happen if parties within the supply chain accept BTC. The volatility of BTC prevents this....