You're right, since the Beta subdomain doesn't look very different.

That makes sense if it is considered to be a subdomain to test functions with which it is being experienced before its total implementation (which will only be done if it is a function that is successful)

Just in case, for my case, I looked for an explanation of what was subdomain on a website and that helped me to see that in reality, it should be normal for it to have consistency in the design because it is part of the main domain.

Source