We once took over a shop that looked genuinely good. Clean, well-photographed, the kind of site people compliment. Then we watched the team try to run it: changing a price meant writing to us, fixing a typo meant writing to us, adding a seasonal banner meant waiting for a deploy. So they stopped asking.
Within a few months the storefront was beautiful and wrong: old promotions, products that no longer existed, a contact page nobody could update. Nothing was broken in the way a developer would notice. The site just slowly drifted away from the business. What it cost was trust, mostly. Customers assumed the shop was abandoned, and support spent its days apologising for prices that hadn't been true for weeks.
Now we treat the back-office as part of the build, not a later phase. Before we talk about the homepage, we ask who will change this content on a Tuesday afternoon, and what they should be able to do without us. If the answer is "open a ticket", the design isn't finished yet. You probably already know who updates your site day to day, and whether they can do it without calling a developer.