When meditating you want to make sure you are as comfortable as possible. Being comfortable will allow you to focus on your meditation practice with much more clarity than you would if you are wearing something like jeans or a shirt that isn’t quite as comfortable as it may be a little constricting.
Wearing specific clothing for meditation also has another amazing benefit where by changing your clothes, it helps get you mentally prepared for the meditation session. Similar to how you wear a uniform to work or specific clothes to the gym. It’s a small ritual that can really make the difference between a good session and a great session.
At the end of the day you want to be as comfortable as possible which is why I have reviewed various different types of meditation or monk clothing so you can decide for yourself.