So it is a matter of time before Shopee review the use of cryptocurrency for direct payment as alternative to fiat.
So the adoption is already on whether Shopee is accepting Bitcoin now or not. They won't have choice by the time another big name opens up within their jurisdiction and sells same kind of stuff they do while accepting Bitcoin. Of course they would begin to lose customers.
No business or store will lose customers just because they don't accept bitcoin in their business, while their competitors do. The future and growth of a business depends on their products, services...and has nothing to do with bitcoin. Don't overestimate the importance of bitcoin, as bitcoin is just an alternative payment method if adopted, not the only payment method. It also has nothing to do with the business operations of those companies.
Using bitcoin as a payment method is just an option because it was created from the beginning as an alternative, not a replacement for any system or currency. This will depend on the decision of each business as well as the legality of each country.
Buddy, it is plausible to state as such, that it is possible to say a business outfit can lose customers if they are not in line with modern practices especially where they have a strong competition and competitors within and around them offering such modern practices as it relates to cryptocurrency. Shopee doesn't offer any cryptocurrency as alternative to their payment platform not even usdt. They only do that through third party and buying of gift card through bitrefill. Sometimes it will maybe inconvenient for a customer to always make payment using fiat. They say "variety is the spice of life", including bitcoin or cryptocurrency in the payment platform of a business is not replacing fiat with bitcoin but still playing the role of alternative payment system. After all those business outfit using Bitcoin have not jettison fiat.
A practical example is the cashless system and depending on your country, almost all micro businesses now own POS machine from where they debit customers with their cards or they receive bank online transfer from customer. The simple truth is that the pressure of business success via competition is forcing those SMEs (Small and Medium-sized Enterprises) to operate modern tech services. Those that are still depending on physical cash are losing their customers, at least this is a practical reality in Nigeria. So Shopee will not continue that way if they have strong competitors.