Speed hooks and spring gaffs are illegal here. You don't want to be found near the water with them.
But if it is a real survival situation every poacher's trick is an option and I would be very glad to be arrested by a park ranger in such a case.
Nets are extremely useful and used to be required in aircraft survival kits in northern Canada. I am not sure if they are still required. The rules were recently rewritten and are not clear at all now.
So, for survival fishing, yeah, long lines, set lines, traps, nets, snares, spears, fish poison, you name it, just as long as it is an effective method of gathering food.
You won't be too fussy about the size or type of fish either. This is not catch and release. Even if the fish you catch are frogs whacked with a stick, the hind legs are still good food when roasted.

The idea of a bit of line and a few hooks is to have something small and easy to carry just in case you need them.
They are not a full kit, and are not meant to be one.
If your kit is too big you will not likely have it when you need it, and I can carry 6 hooks and a length of fish line on a card in the credit card pocket of my wallet.
So a small simple kit, not everything you want, but what you should at least have with you.
It is the same reason we carry a small length of wire for light snares, not enough for a real trap line, but enough for a few rabbit or squirrel sets.
Plus the fish line and wire often have other uses.