Learn Italian: Questo vestito non è originale, bensì molto antiquato. - This dress is not original, but rather very outdated.

You absolutely can use ma, but bensì is stronger and more precise. It specifically translates to "but rather" or "on the contrary." Its entire job is to replace a negated idea with the actual truth, elevating your Italian to a higher level of precision than just using ma for every "but".

Does bensì always have to follow a negative statement?

Yes, it does. Because bensì is a connector of substitution, the first part of the sentence must contain a negative (like non è originale) so that the second part can offer the replacement (molto antiquato). You cannot use it to just add contrasting information to a positive statement.

How would this sentence change if I wanted to use al contrario instead?

Bensì connects the two adjectives neatly within the same clause. If you use al contrario (on the contrary), it functions more like an introductory adverb for a new thought, so you would typically repeat the verb: Questo vestito non è originale, al contrario è molto antiquato.

Why is the word antiquato used here instead of antico?