Yes, if you know how it works and how SharePoint works. 99% of the “site admins” don’t.
I’m in two big projects now, going from on-premises to Office 365. Guess what’s stopping us from some upgrades — scripts. Scripts added to pages to do this and that, scripts created by happy admins, that has now left the company since years, scripts relying on the DOM preventing usage of the new Modern sites, scripts that are “business critical”. It’s all Notes to SharePoint migration all the way again.