Can anyone here tell me the reason why MB used that replaceable plastic key head on the keys? I replaced mine about 6 months ago now it's torn again. I can't think of a good reason why they did that.

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'02 BMW 325i
'85 300D 450k
'93 190E 2.6 170k(killed by tree)
'08 Ducati Hypermotard 1100S 6k
'06 Ducati S2R800 14k(sold)