First, regarding the other comments, they should probably be deleted too. The reason yours was singled out is probably because moderators usually delete flagged comments, because their attention is drawn directly to them and with enough flags a comment can be automatically deleted by the system too.
Comments are only supposed to be used for making suggestions, giving constructive criticism which relate to the post they address and giving hints that might lead to an answer, without answering the question. Attempts to answer a question have no place in the comments and there are many possible reasons for that. You should not be posting suggestions for the word as a comment. You should be writing answers, preferably with an explanation regarding why you prefer those suggestions and evidence to prove those points to make it useful.
The system is predicated on answers being posted as answers, and many forms of harm arise when they are posted as comments instead. Most of these harms probably will not make much sense to you, since you may not yet be entirely indoctrinated into the Stack Exchange philosophy but allow me to explain the most important one so it does not seem like an entirely senseless policy:
Comments which suggest answers clutter up space meant to address how the question can be made into an answerable question, and especially since they tend to elicit uninvited extended discussion regarding the validity of the answer. Also, once a certain number of comments are made, the rest are hidden from unsolicited viewing, and preference towards which comments are displayed are given to the ones most often marked as useful, as agreeable answers often are.
This combination of factors makes it harder than is necessary for people to find any comments which are actually serving the intended purpose of our commentary system and most especially the questioner, because they will have to read through all of the comments to see which ones are trying to address problems which may otherwise end up leading to the question's closure for any one of what I believe to be six or maybe seven common reasons. I would list those reasons, but question closure is beyond the scope of this question.
When an answer is posted as an answer, it gets its own commentary space for the comments it elicits which are less relevant to the question, and more related to the answer itself.
Now you may think you are helping by making quick suggestions which might solve the original poster's problem, but without explaining why those words are good suggestions, and how they can be used to solve their problem they probably will not realize why these words solve their problem or how they fit their given context. If it is a common word, they may have already considered it and dismissed it without understanding why it is the best word for their situation, and if it is a rare word, they probably do not know what it even means without needing to consult a dictionary and may still need further explanation to validate the answer. Anything worth suggesting here is probably only worth suggesting as a fully independent answer.
NVZ already mentioned that comments are only transient. It helps to keep the website looking neat, and the focus attention on the questions and answers themselves.
For more information regarding when you should, or should not comment, please read the help center's commentary guidelines.