3 keys are enough- except if you have Alzheimer's disease and cannot remember where you put your key.
I received 2 Remote keys with my Swift and one simple one.
Even BMW and plenty of other Car manufacturers only supply 3 keys, in fact, BMW's 3 series, only gets 2 keys.
One of the main reasons why the third key has no remote and is completely simple- It's called a " Surfer's key ". You keep that key with out, say you go for swimming and other activities, where you could damage the electronics inside your key.
Or when you give your car to a Valet- You can lock the glove box and the trunk cannot open with the third, simple key.