WhatsApp for web was first introduced in 2015 but was just a mirrored version of the mobile app. Which means, unlike Telegram web, WhatsApp for web still needed your phone to be online for it to work. According to WABetaInfo, that might change soon.
According to a tweet posted from the WABetaInfo account, the company might be developing a Universal Windows Platform (UWP) app alongside a new multi-programming system that will enable WhatsApp for web work independently. This is the same way that Telegram for desktop works.
With the new implementation, you will be able to connect with your WhatsApp contacts on the go even if your phone is powered off.
There is no specific timeline when to expect this feature, however, we will keep you updated when we spot more news on the same.