The answer to this is yes and no. Dictation has a few advantages in that it helps you improve your micro-listening skills. This means that listening to every word may help you with identifying features of speech that connect ideas together, eg. referent words (he, she, it), prepositions (of, over, in), articles (a, an, the) and so on. Basically, it lets you understand speech a lot better by getting you to recognise different sounds when people speak at a natural speed. It also good to train your spelling skills this way.
So, in the IELTS Listening context, dictation is great for Section 1 where you will need to listen for specific information, such as filling in forms or completing a table, that requires you to write names, phone numbers, addresses, dates, etc.
However, there is another side to being able to do well in the IELTS Listening. For example, what you see in the question may not be what you hear in the recording. Synonyms are quite often used in questions and this depends on your vocabulary to be able to interpret what you hear. In IELTS Listening, you may also need to watch out for the speaker’s stress and intonation to understand their attitude or know what he/she truly means.
A common mistake that IELTS candidates tend to make is to try to capture every single word that they hear in the recording. This is an almost impossible task and the WRONG way of doing this test. Imagine looking out the window while travelling on a fast train. Can you capture every single tree that passes by? If you do this, you will only give yourself a headache! Yet many candidates do just that in the IELTS Listening test and then give up.
Overall, if you are using dictation to help you with your listening skills, keep doing it to help you improve your micro-skills. But you should not depend only on dictation to help you get that IELTS Listening score. Do some dictation, but don’t let this be the ONLY way of preparing for the IELTS.