100% agree. But the conversation is mostly with deciding what the default denomination would be(e.g. on Coinbase, on CoinMarketCap, etc) instead of the default BTC that we’re currently using; not necessarily the one and only denomination that should be used.
All the three dominations are used. I remember when I was still novice and using faucet and pay to click sites to collect bitcoin, the amount collected was represented in satoshi, mbtc and btc, also I have seen crypto betting site recently having campaign on Bitcointalk forum that represent bitcoin in mbtc. While also you can choose the denomination you prefer on some wallets. We can use what we wish among the three. On exchanges and on sites like coinmarketcap, the domination of bitcoin should be btc, nothing should alters that for people (newbies) not to confuse.