A german youtuber tested culverins against springalds. He e.g. considered different building costs. Culverins won clearly. There are some reasons like culverins can one-shot springalds and you can repair culverins and it is difficult to focus one culverin with many springalds and so on. So do tests.
I saw a lot of games with people making springals and mangonels. And with that alone in good numbers erased waves and waves or armies and their bases xD
Siege is crazy