Learn Croatian: Zahvaljujući inovaciji, interes za proizvod brzo raste. - Thanks to the innovation, interest in the product is growing fast.

It follows the preposition zahvaljujući (thanks to). This preposition always requires the dative case to show who or what is responsible for a positive outcome. Here, the feminine noun inovacija changes its ending to -i for the dative form.

Could I use zbog (because of) instead of zahvaljujući in this sentence?

Grammatically yes, but it changes the tone. The preposition zbog is neutral or negative, whereas zahvaljujući is specifically positive and beneficial. Since an innovation boosting interest is a good thing, zahvaljujući is much more natural here. Note that if you used zbog, the noun would have to be in the genitive case (zbog inovacije).

Why is proizvod in the accusative case after za?

When za expresses purpose, target, or direction (like interest directed towards a product), it takes the accusative case. It only takes the instrumental case when describing a static location (meaning behind). Because proizvod is a masculine inanimate noun, its accusative form looks exactly the same as its nominative form.

What is the aspect of the verb raste?