Why are [] runes no longer used around label runes?

The #compudanzas guide used to have label runes like this:

|00 @System [ &vector $2 &pad $6 &r $2 &g $2 &b $2 ]

but now the uxn tutorial looks like:

|00 @System &vector $2 &pad $6 &r $2 &g $2 &b $2

for exactly the same example programs.