Checking market movement as an long-term holder shows that you are just in for short-term goals. Because as a long-term investment one don't need to bother themselves with price movement, instead focus on how to accomplish their accumulation goal by accumulating and same time holding for long-term. Yeah checking the market movement on a regular will definitely messed with one emotions expecially those who are new in to Bitcoin which may lead to one selling their investment in a premature state.
That is not always true, I have been a long term holder for a long time but I have been checking the daily movements for years as well, there is nothing wrong with checking the price and the movements, it allows me to buy more when it drops a lot, like for example with this recent drop I bought some more, not a lot because I have absolutely no money left, it was literally just 30 dollars, it is nothing compared to what people invest, but that is what I had, and I didn't want to miss this chance.
So, just because you are looking at movements daily, doesn't mean that you are going to make a move, or doesn't mean you are going to sell, it just means that you would like to stay informed with the market you are invested in, that's it.