Encoder/decoder is much, much more efficient for finetuning and inference than decoder-only models.
Historically T5 are good when you finetune them for task specific models (translation, summarization, etc).
Historically T5 are good when you finetune them for task specific models (translation, summarization, etc).
Also a hint: you can create a finetuning dataset from a frontier LLM pretty easily to finetune those t5 and effectively distill them pretty fast these days