Debugging Input Representation in a Sequence-to-Sequence Model

Example of a T5 Machine Translation Training Sample with Special Tokens

In designing a sequence-to-sequence model, an engineer decides to use one specific start symbol for all source sequences fed to the encoder and a different, unique start symbol for all target sequences fed to the decoder. Which statement best analyzes the primary benefit of this design choice?

In a sequence-to-sequence model, using a single, identical start symbol for both the source (encoder) and target (decoder) inputs would make it impossible for the model to distinguish between the two types of sequences and thus prevent it from learning the task.

Formulating NLP Tasks as Sequence-to-Sequence Mappings using Start Symbols