People buy XMR with bitcoins, not dollars. That chart isn't so cheerful.
First of all, XMR has plenty of of USD transactions. Here are the two "reputable" exchanges that offer USD pairs:
Kraken XMR/USD volume: $536,000
Kraken XMR/XBT volume: $830,000
Bitfinex XMR/USD volume: $846,000
Bitfinex XMR/BTC volume: $557,000
And yes, there's Binance and other reputable non-USD exchanges that do millions in BTC volume, but you have no idea how much of those trades are real.
Secondly, just because more people trade with BTC, that doesn't mean they're not watching USD charts or are unaware of the USD price.
That is completely true, I currently am only trading in USD, USDT and a very small amount in BTC basically because, I don't want to lose the BTC I have
and it is still important to me to increase my USD networth! I only use Tether for short amounts of time, as a replacement for USD.