A beginner does not need to learn how to use a capo but this device can be useful since it gives an easy way to play in other keys without learning new chords. This can help you match an experienced singer with your early skills.
The issue with this is that while at first, it may seem like a huge advantage, it can also turn into a big downside since using a capo can easily become a learning prevention tool. This is the reason why many music instructors don’t recommend beginners to use a capo.
It can be useful when used sparingly, but relying too much on it can slow your learning experience down. Thus, as a beginner, you do not need to invest in a capo if you don’t need it, but there’s nothing stopping you from getting one if you wish to. Most tutors would advise that as a beginner, it is much better to invest your time and money in lessons and practice.