And since they live a long time it's given us an out every time he asks for a new pet ;)
Having kept them before, they are genuinely about as hard to care for as goldfish but need bigger tanks and a little bit more cleaning.
Also super easy to breed, we let the spawn hatch once and ended up with about 70 larvae, they cannibalize quickly but 6 grew to full size and we sold them on very easily.
Also note most goldfish are abused, they need huge tanks 40G+ if I remember right, and not the 8-16 fl oz bowls they're stereotypically kept in. And they need filtration and would do better with a water heater. So idk if pointing to goldfish is the best indicator, even if imo you're technically correct - the refrigerating system isn't really a lot to maintain and that's the main difference.
Hopefully we kept them well. We had them for years and in that time they spawned regularly, ended up giving our original pair up for adoption when we moved house.
Tank was smaller than 40g. You're right though bigger is better, that's the general advice with all pets (including goldfish which can grow huge!).