apologies if this question sounds ignorant but when I use voucher code on a product of a 3rd party seller, who bears the discount. lazada or the 3rd party?

Link

TL:DR zalora and lazada is making lost every year but they have huge capital.This is not small time website like mudah. They projected to make profit within 6-9 years.Keyword = branding

But no matter how good branding in future. After they start stop or reduce those good voucher in future in order to make profit, it wont be anything different than lelong.
Lelong is well known in malaysia online shopper, here comes lazada, in future lazada famous then might come others eg. Taobao.my or alibaba.my.
Im not good in business. But really doubt this kind of marketing strategy works not