But are you a software developer or a lawyer? Do they 'not need it' because the government provided a way to ensure it's not needed or because your interpretation of the law indicates it's unnecessary? Are you willing to indemnify them for legal costs if your guidance was wrong?
Most small business owner's I've spoken to are keenly aware they are only one bad lawsuit away of closing down. Almost no one care's about the cookie banner. Most just mindlessly click to allow cookies and go on with their life. There's almost no cost to having it.
The 'better safe than sorry' calculation of small businesses skews almost 100% toward 'safe' because almost all govt regulations contain no reasonable size scaling cap on penalties. Any penalties on a website that are per-occurance could be almost infinite.