DCA does not have these disadvantages. On the contrary, it has a huge advantage in that the DCA investor has a lot of free time, during which he can think about how to increase the volume of monthly investments.
Apart from that when you are investing with DCA, it gives you time to involve in other business and go on with your daily activities. DCAing is like you are not investing because you only buy when you have the money and forget about it, till the next week that you want to DCA. Unlike trading that will exhaust your time, mess with your emotions and will make you run at loss at the end.
Looking at the market chart is not really a bad idea or bad thing per say, as a matter of fact checking the market is what makes an investor to be updated on what is happening. If I may ask how will an investor know if there's Dip if he or she doesn't check the market?. Well everybody have there reasons why they check the market and the only time the market will look annoying is when one invested for a short period of time or you are gambling it but if you are for long term you need not worry because there's going to be b a pump, so the advantage of checking the market is to know when there's Dip and also keep an investor updated.
I don't think that looking at the market often is necessary for a bitcoin long-term investor because he has the chance to know the price of bitcoin if he is on a weekly DCA approach since he will always buying every week. Also if you are always updating yourself on bitcoin news and others, you will definitely know about the price of bitcoin within the week. I always read cointelegraph.com latest news and when doing that I see the price of bitcoin, sometimes due to my busy schedule during the week, it is only when I want to make my weekly DCA purchase that I see the price of bitcoin, and I am not worried about the price since I am not planning to buy at the dip due to lack of funds for buying at the dip.
It is only invstors who are planning to buy at the dip and traders that often check the price of bitcoin. Market chart is not important for a new investor who just started his bitcoin journey.