So, to say dependently-arisen phenomena are "like" an illusion, implies a subtle clinging to some sort of "reality" of dependently-arisen phenomena.
Its the reality you've yet to see! Think positive. Should we not talk about the path because it implies a clinging to enlightenment?
The problem doesn't go away if one says dp-phenomena 'is an illusion'. The implication here could be that behind the illusion is an illusionist. Its an assignment from general to specific - like saying 'fruit is apple' instead of 'apples are fruit'.
But if we use the simile 'Fruit are like apples' this is acceptable, if a bit awkward, since some fruit are not only like apples - they are apples. 'Fruit are like apples' is how anyone would explain the concept of fruit to a child. What should a child think if you told him 'fruit are apples'? Its only partly true.
The disciples are like the children and dp-phenomena is what they want to understand, where they already know what dreams and illusions are. If they think there is some deeper meaning behind 'like an apple', they might go one of two ways:
In the 1st they think there must be bananas and pomelos - something besides apples that can be called fruit.
In the 2nd they could suspect the designation 'fruit' to be an empty one.
So then is the illusory-ness the only characteristic we can comment about dp-phenomena? Isn't the designation 'dp-phenomena' an empty one? Surely not, and surely it is.
Therefore its important to use 'like' so that we are not tempted to conclude that we have understood dp-phenomena merely by hearing of their illusory-ness. With such grand scholarly topics as these we should be cautious of overestimation, not modesty.
I don't accept these:
'fruit is apple' - 'appearances are illusion'
'fruit is an apple' - 'appearances are an illusion'
'fruit are apples' - 'appearances are illusions'
'some fruit are apples' - 'some appearances are illusions'
'fruit are like apples' - 'appearances are like illusions'
'fruit is applelike' - 'appearances are illusory'