The answer is simple: It depends on how much rotation you want to achieve. The greater the amount of rotation, the more of a hooking action you'll need.

Hooking your foot creates a very tight rotation around a small circle, while walking backwards causes a more progressive (or actually, in this case, regressive action) around a broader circle. So in a sense, they're both right... they just prefer a different quality of movement.

If you're asking who is more "correct" in terms of book technique, again, it depends on which book you look at, and how you interpret it. But most of the suggest some sort of crossing action. For example:

The older ISTD Latin Tech book reads: "RF Behind LF, Toe to Heel, Toe Turned Out", leaving some room for interpretation. However, lower down in the notes it suggests that the feet are indeed crossed. It also mentions that the heel of the RF should not lower until the LF begins to move, which is indicative of a cross.

The newer ISTD Cha Cha and Rumba books read: "RF behind LF (Cuban Cross)", the Cuban Cross being a very specific foot position where the feet are crossed, or at least, in 5th Position.

American Style books all vary, but most of them use language such as "RF Crosses behind LF", indicating a delayed lowering of the right heel, which is only necessary if you're crossing.

Me? I too prefer the cross, because I like to dance my Back Spot Turns with tight, quick rotation. But I don't deny anybody who prefers a broader turn without a hook. I think they're both technically possible, and therefore, "correct".

Sincerely,
Jonathan Atkinson