When Overwatch 2 replaces the original Overwatch on Oct. 4, players will be required to link a phone number to their Battle.net accounts. If you don’t, you won’t be able to play Overwatch 2 — even if you’ve already purchased Overwatch. The same two-factor step, called SMS Protect, will also be used on all Call of Duty: Modern Warfare 2 accounts when that game launches, and new Call of Duty: Modern Warfare accounts.
Blizzard Entertainment announced SMS Protect and other safety measures ahead of Overwatch 2’s release. Blizzard said it implemented these controls because it wanted to “protect the integrity of gameplay and promote positive behavior in Overwatch 2.”
SMS Protect is a security feature that has two purposes: to keep players accountable for what Blizzard calls “disruptive behavior,” and to protect accounts if they’re hacked. It requires all Overwatch 2 players to attach a unique phone number to their account. Blizzard said SMS Protect will target cheaters and harassers; if an account is banned, it’ll be harder for them to return to Overwatch 2. You can’t just enter any old phone number — you actually have to have access to a phone receiving texts to that number to get into your account.
Blizzard said these phone notifications will be used to approve password resets — meaning someone else won’t be able to change your password without the notification code it’ll send to your mobile phone. Blizzard said it will also send you a text message if your account is locked out after a “a suspicious login attempt,” or if your password or security features are changed.
Source: Overwatch 2 SMS Protect: What is it? Why does Blizzard require my phone number? – Polygon
So this is a piece of ‘real’ information you have to give them – but what if you move country and mobile phone? what if you lose your mobile? what if they get hacked (again) and take your number? It’s either something that does get changed or is very hard to change. It shows you that basically Blizzard sees your data as something they can grab onto for free – you are their product. Even though the games are technically free to play, in practice they make a killing off the items you buy ingame in order to be cool
They will probably get away with it though, just as they got away with installing spyware on your PC or when you attend their events under pretty flimsy pretenses.