Perhaps they should have sold it as being value at so much per kg?
There is an ideal balance between weight for stability and excess which will be a pain - literally with some - which must vary with the individual. But 4 kg for a cordless drill I'd say is far too high for any normal soul.
The other thing that may not matter to some, but does to me, is that when the battery fails - as it will - replacing the cells with decent quality ones makes a vast difference to the performance of the tool. I've got a B&Q 18 volt where this is definitely the case. And new cells for that cost about the same as a new drill. At 32 quid for a 24 volt, they'd cost considerably more. Not that you'll find the same drill at the same price by the time they fail anyway.