The clip is sold originally as an individual component (PSA OE 4341.14), but at a cost far exceeding the value of the cables - and therefore making a repair costly.
As a cheaper alternative, the clip is sold as part of a set (PSA OE 4333.05 and Fiat OE 9949473 - but only as a set of two clips and two springs). The springs do rarely break, and therefore there is no reason to pay for a whole set, of which only half is used.
Triscan supplies, as the only one on the aftermarket, the clip as an individual part in the absolute most affordable version (Triscan ref. 8140B20). Thus, you do not need to order something, which might not be used and this way you reduce the customer’s expenses.
Clips on handbrake cable