First of all, I have to ask: why did the manufacturer choose an internal, non-removable battery? I don't see how they can squeeze money out of the manufacturing process, since designing a removable battery is, I believe, just a problem of case molding. A removable battery can also be sold as an accessory, creating more revenue.
And one day the battery on my shiny new Dingoo will fail. Will I have to buy a new Dingoo just to replace the dead battery?