Ok, this all works as expected:

λ> data Point = Point Float Float deriving (Show, Read)

λ> Point 1.0 1.0

Point 1.0 1.0

λ> read "Point 1.0 1.0"

*** Exception: Prelude.read: no parse

λ> read "Point 1.0 1.0" :: Point

Point 1.0 1.0

But now we add names to the values in the Point, and things change:

λ> data Point = Point {x :: Float, y :: Float } deriving (Show, Read)

λ> Point 1.0 1.0

Point {x = 1.0, y = 1.0}