A Battle.net account runs everything Blizzard — World of Warcraft, Overwatch, Diablo, Hearthstone — and a linked phone number is woven deep into it: SMS Protect handles account recovery, unlock codes after suspicious logins, and some titles have outright required a phone on the account to play ranked or free-to-play modes. A virtual number from Get-SMS satisfies those requirements without your personal SIM.
Blizzard is famously picky about number types: prepaid and VoIP ranges are often rejected with «this phone number cannot be used». Numbers on Get-SMS come from real mobile operators, which is exactly what Battle.net wants to see. If a specific number still doesn't pass, cancel it free of charge and try a different country — US and European pools have the best record here.
Blizzard binds a phone to a single account: attaching it elsewhere removes it from the previous one, and an account without SMS Protect falls back to email-only recovery. For a main gaming account that will hold purchases, we recommend the 30-day rental — Blizzard sends unlock codes by SMS whenever it dislikes a login location, and games with regional pricing make VPN logins fairly common. For a quick secondary account a one-time activation is enough; just keep the recovery email healthy afterwards.
The phone's country code has no effect on game regions, server choice or pricing — those follow the account region set at creation and your payment method. Pick the number pool purely by price and availability.