There's never really a good reason to omit an app drawer on an Android device the feature lets users organize their home screens better since not every installed app needs to be there.
Taking note of this is Xiaomi, who will finally be adding app drawers in MIUI 11. Some devices have had the OS rolled out via OTA already, but the app drawer feature is still not yet available. Xiaomi took to Weibo to announce the feature and say that it will be introduced in an upcoming launcher update.
Xiaomi or Redmi users will soon be able to switch from 'Classic Mode' or 'Drawer Mode' in their settings to enable the feature. The update is currently rolling out to users in China, so the global release should be soon.