Why is it bad to testify in your own case? I have heard this from time to time but have not understood it. Is it not your chance to tell it like it is?
Your lawyers can poke holes in the prosecution's case ("cast doubt" on it). Make it look like a weak case.
Getting on the stand and explaining an alternate timeline actually give the prosecution MORE evidence, from the horse's mouth. They can find new things you did wrong, they can find inconsistencies in your story, inconsistencies between what you said today and what you said last week. You're likely to commit perjury.
You're not expected to convince the jury of an alternate timeline, you just need them to NOT believe the very specific one the prosecution lays out.
For a witness, this really just means more stress than you were likely expecting going into the process. For someone actually involved in the trial, I imagine it is everything multiplied.
When you are super guilty, that typically doesn't go well.
But who knows, maybe having his bail revoked gave him some perspective of how seriously he should take this and that he isn't a legal genius.