Some chain applications:
Chain:1
As you stated, it is the default for spells, but Chain doesn't only apply to Spells.
Permanents and Creatures can have this ability too.
Example:
Antlion
(normal burrow effect)
Chain:1
(May) Destroy an opponent's Pillar.
Obviously, could be overpowered with Fractal, but it is just an example.
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Creatures can be given Chain:X, where the more that are put in play that turn can give either a positive or negative effect.. The latter can be a deterrent to Fractal. With this cards that were balanced in every way, except when Fractal'd would now be perfectly fine.
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Any more examples?