In addition to what you have said, if someone is saying that the reason why the investor should monitor the market is to know when to take a buying advantage, Instead of continuously monitoring the market, and going through the emotional torture associated with it, the investor should set price change notification alert on, and set up that price level that he should be notified. So that once bitcoin hit that price level that the investor has set up, he will be notified by his exchange or wallet app.
This is more effective way than for the investor to be updated about price changes, than continually monitoring the market. We live in a world where technology has simplified everything, unless the investor has other reasons of checking the market, other than just knowing when there is a significant change in price in bitcoin market.
Market observation makes a person aware of the market position. Whether you are a trader or an investor, market observation will help you understand price movements. Being aware of the ups and downs of the market plays the most important role for a deep investor.
If a DCA investor wants to be aggressive in investing during dips then it is positive for him to prepare to be aggressive by watching the market. There is no harm in market observation if you can prevent yourself from the negative effects of market observation.
If you are afraid of unstable market conditions or market observation makes you think of selling investment when the price rises or falls then you should refrain from market observation. Embrace the positives of market observation and avoid the negatives.