Advantages of subsidies over tariffs;
1> The company gets the subsidy immediately, not dependent on sales, which lets them make up shortfalls in development and become competitive in the marketplace.
2> The savings get passed on to the consumer. Tariffs increase prices on imports, which raises prices to consumers indirectly. Subsidies are better for the working and middle class consumers.
3> Tariffs create greater international conflict over trade protectionism than subsidies (which still produce some, just not as much).
4> Subsidies generally act to make a more fair international marketplace with greater parity in costs, minimizing any chance that your citizens can save money by crossing the border to buy cheaper, non-tariff-inflated items.