I was bullied by state, even my hosting provider was bullied. I was bullied by police, that was acting directed by huge gambling company. I had my property seized. And you know why? Because I was an idiot who did not use who is privacy, who used wrong hosting and who was naive.
Maybe this does not happen in every state. Maybe. Now. But look around you. What is happening with the world. Look about the "bad actor" in the US for example. Issues like that are in every state. Every state has problems how to collect taxes. Every state will going towards stricter regulation and licences. And every licensed company will try to maximalize returns and will lobby by the state where they pay taxes. And such joint venture of the states and the big companies will be a mess across the economy.
Not your problem? Are you UK based affiliate promoting UK licensed business only and not planning more?
What about the time when criminals will start target people on traffic estimating tools? It already happened. Are you small affiliate now? Wait for the time when you grow to #1 and you will sweat about the trace you left when you had 3 registrations per month.
There are so many reasons why to hide your own privacy, of course not only with who is protection. I do not care personally that much about who is protection, it can be achieved by other tools and if one uses only whois protection, the site is quite easily traceable as well.
If you talk to God, you are praying; If God talks to you, you have schizophrenia.