If you do it right, automated recommendations work also for smaller customer bases. There's a lot of redundancy in customer and product data that can be exploited to generalise the behaviour of groups of customers over groups of products.

Doing this automatically is a huge positive ROI thing over manual curation. In fact, humans are not even that good at coming up with good recommendations. Manual re-arrangement has almost universally been an anti-relevance feature in A/B tests I've looked at.

But of course, almost nobody does the automation right.