The common toad is a land toad it will not last all that long under water. Also when threatened it will put off a hideous tasting foam from the two big warts just behind its eyes on its back. That is the toads defense. So, in answer to your question, I say no I don't think they would do good as bait but , also, you never know till ya try.
I never used toads but suspect they probably aren't that good. I know they secret a mild toxin from the two nodes on either side of their head when they are aggavated or injured. It's a sticky milky fluid that just slowly oozes out. I know it will cause a dogs mouth to get all foamy if he messes with one and I think that's why dogs and cats usually leave them alone.
a few years back we went to the great salt plains lake in oklahoma and it seemed that toads were the bait of choice by all the locals.there were toads all around the lake so it made sense to me to catch a few and try em.my first fish was a 15lb. channel within 10 minutes.we used toads and grasshoppers all weekend and tore em up
When I was in the Boy Scouts and working hard to EARN my Merit badges I used tiny bull frog hoppers as bait. Caught enough blue gills to manage to clean, cook and make the required meal from them. It was a very windy day and my troop leader did not dock me for the dust and dirt that he had to eat while judging my (Fantastic meal). Thanks for helping me to grow to be a MAN... (Thanks to all Scout leaders)!!!
I have used small common toads for channels for close to 50 years. they are great bait. catch them when they are the size of your thumb. I fish them both on the bottom and under a float. I have caught channels up to 20+ pounds on them.