Well, as an introvert myself, I would say yes, there are disadvantages. You can't express yourself to anyone, letting people walk all over you.
You try and bail out from social gatherings or tours which reduces your outdoor activities and social life.
Being all alone affects your mental health too.
These are just a few. But hey, you can't just change who you are, so it doesn't really matter. hre will always be drawback, either if you are an extrovert or introvert or ambivert, so just be yourself.