The difference is that you know offhand how to do one of these things but not the other.
Answering the questions is not intended to improve the security of your business, it's a form of serving your customers.
My personal experience with the ICO has shown their quite lenient to mistakes, if you can show that you’re your honest best, and getting better.
No point crushing companies that are trying, better of getting the ones that just don’t care.
But it's not even just about getting to a point of getting fined or under some kind of investigation or audit. It can be all those clever customers who would use some automated service or a template, just to waste your time ... At least that's what the original post is about, but I hope it won't be too common.
Around here, regulators are prone to scoring easy points by going after the small, naive fish. All it takes is the wrong incentives: the department needs to show results, so it gives bonuses, or establishes quotas for successfully handled cases. Bam, your small business is now investigated because a government employee needs to meet a quota and correctly guesses you can’t afford competent legal defense.
It's very different. Here you're requested to answer fairly detailed and potentially tripping questions with potential legal implications on your business. This has little with how you secure things technically. It's all about jumping through some bureaucratic hoops, and wasting your time doing it. Answering those questions won't in any way, shape or form improve the security of your business. It's pure distraction.