Change WooCommerce add_to_cart Button Text?

It’s not working because:

get_the_terms( $post->ID, 'product_cat' )

yields an array of objects, to test against those objects you have to run a loop and pull a $term_id property out of each object.

WordPress to the rescue! WordPress has a helper method for that…

has_term(330,'product_cat', $post);

Use the has_term method to satisfy your conditional.