Use case(s) for owning a homelab?

So I was wondering, what is exactly the use case of owning a server rack with huge CPUs and 256GB of DDR4 RAM with 1PB of storage?

Obviously, I'm kind of exaggerating here, but it does seem that most homelabs are big server racks with at least two CPUs and like 20 cores in total.

Why would I want to buy a server rack with all the bells and whistles when a low-power, small NAS can do the trick? What's the main advantage of having a huge server, compared to an average Synology NAS for example?

Honestly, I only see disadvantages tbh. It consumes way more power, costs way more money and the processing power it provides is probably only relevant for (small) businesses and not for an individual like me.

So, convince me. Why should I get a homelab instead of a regular NAS?