When choosing a quote currency you will want to consider how much you can gain to increase your quote currency market share over time. You will want to choose a quote currency that is easiest to trade successfully as many times as possible. That being said the recommended quote currency is TETHER (USDT) for beginners as it is the easiest to trade and gain on. A quote currency such as Bitcoin or Ethereum have historically been extremely difficult assets to gain on, as they continually have increased in value through their lifespan on the macro level. Fiat currencies such as USD, EUR, AUD are inflationary therefore lose value over time, whereas assets such as BTC are deflationary as there is a fixed supply and less being mined every 4 years due to halving events.
Intermediate traders can use any number of quote currencies and adapt any Killer Whale strategies to match your trading style. This can be achieved through backtesting strategies against trading pairs with your desired quote currency and editing Take Profit, Trailing Stop-Loss, Trailing Stop-Buy and Stop-Loss settings to match your desired trading frequency and duration.
Need to know more about backtesting, refer to this article > How do I use backtesting to achieve my desired result?