I personally think it’s better to keep your domain registration separate from your hosting/cloud providers, including cloudflare. Basically not putting all your eggs in the same basket. Those giant cloud companies probably won’t be going anywhere anytime soon, but their automated system are known to ban users with no recourse unless you’re a big spender with dedicated account managers. Having your domain elsewhere means when something happen to your hosting/cloud account, at least you’re not completely fucked.