[Question] Why does text-only data use the empty image token?

[MSungK]

Question

Text-only data is implemented in such a way that learning proceeds with visual tokens set to empty. In my opinion, since the length of visual tokens is quite significant, it seems more efficient not to use meaningless visual tokens for text-only data. Moreover, since a sampler that samples data from the same modality is already implemented, I am even more puzzled.
Is there a specific reason for this?