I do agree with your statement and what keeps bitcoin from being a true cryptocurrency is that it was treated as a holding. But the problem nowadays with bitcoin is that it is not so merchant friendly since when they accept bitcoin and its value fell down they will suffer also from the price drop.
But for merchants if bitcoins value is at dip it is a good time to accept cryptocurrency or bitcoin since if its value goes up you will earn a multiple times of profit from your sales because of btc.
All of you make good points, however, when you accept BTC you receive fiat. Payment processors convert it to fiat for you, it's just like accepting Visa and Mastercard.
While it is tough to open an online business, there are a lot of needs by people in this community that go unfulfilled. A lot of people are cash poor but have crypto income from mining ect. You give them the things they need everyday and they will buy from you. Hold a bounty right here to promote your store. It takes time, knowledge, patients, and resources. But if you have the heart to be an entrepreneur, you enter into an untapped market.