Some checkboxes are ceremony, some have real purpose. One size does not fit all.
You have a perfectly valid reason, which is that your auditors want you to buy an expensive certificate to make them happy, but you're still paying more than market ($0ish) for SSL, which means you're a good customer for DigiCert to have acquired.
BTW, if you want to save some money, try sending your auditors the WebTrust audits that Let's Encrypt has passed just as well as Symantec (if not more well, see mozilla.dev.security.policy): https://letsencrypt.org/repository/
Whether it's ceremony or not, I have to check the box or face harsh regulatory penalties.
I'm a little amused (not at you, but at the absurdity of the whole process) that we're talking about CA selection for products that almost definitely can't even properly quote and unquote a FIX field separator from user input.
And I think it makes sense for DigiCert to buy it: Symantec's customers are people who are clearly willing to pay too much for even a low-quality certificate because they let Symantec consultants set up their trust infrastructure years ago and have no idea how to modernize their infrastructure. If you want a target market of people who will pay lots of money for CA services despite the presence of free services like Let's Encrypt, Symantec's existing customer base is a perfect fit.