Markets works on the assumption that you are selling broadly the same thing in each country, with local differences in currency, price, language, available products and delivery. Under that assumption it removes an enormous amount of duplicated work, because a product edit, a theme change or an app configuration happens once.
Separate stores make sense when the assumption breaks. Different assortments because of regulation or licensing, different suppliers, different payment methods that need their own gateway relationships, warehouses and teams that operate independently, or a market whose merchandising calendar simply does not match head office.
A useful test is to imagine a routine week. If a product launch, a price change and a homepage update would be identical in both countries, one store with markets is doing you a favour. If each of those decisions would be made by different people for different reasons, the second store is not overhead, it is accuracy.