I guess they're for gamers who take it so seriously their hands sweat and slide off normal keys, typists in a humid country would want a full set...
$30 isn't much in this hobby and I agree that they look good but how long the texture will last I have no idea, Ducky doubleshot caps are good quality so I would hope these are too.
As to how they feel and whether you would like them we don't own your fingers so cannot say. Some people like shined ABS, others prefer new rough PBT and these in rubber will feel completely different to both of those. Could always put them on your Christmas list, better than a festive jumper