You are not supposed to use this website so UX really doesn't apply.
This is the Mastodon instance of official EU accounts, not a website where you can sign up. You can follow any of these official EU accounts from other Mastodon instances since Mastodon is federated. Your gateway to Mastodon is the website of the instance where you sign up or one of the many Mastodon client apps.
What would likely happen is that you see something "retweeted" (boosted) on your timeline by some other account you're following and this perhaps makes you aware of one of these official EU accounts, the exact same way it works on Twitter. You don't need to care about the fact that it is posted on another instance, however in this particular case you can consider it a form of verification.
