Yeah, I assume this is a dual purpose morale booster and demoralizerm Ukraine shows that Russias defenses are a paper tiger because they relied on threats and it will force Russia to respond with troops, either by pulling from the front lines or reinforcements. Either way it moves the fighting to Russian land and that will demoralize support in Russia.
Plus they can disrupt more supply lines and war manufacturing locations by going around the border defenses. They don’t even need to hold ground, just be a thorn in Russia’s side.