So, according to an author friend of mine, the Chicago Guide to Style does not allow exclamation points. Their reasoning is that the verb in the sentence should be strong enough to convey the emphasis without the added punctuation.
I agree with this for the narrative, but I have to disagree in the case of dialogue.
Exclamation marks serve as a sort of shorthand or a visual cue, letting readers know the tone before we get to the verb.
“I gotcha!” the policeman bellowed.
“I gotcha.” the policeman bellowed.
The second is confusing to me – I read the dialogue in a subdued monotone and then reach the strong verb telling me that I should have read it as a shout.
The first one lets me know ahead of time that the tone is far more animated than usual, while the verb confirms it in the end.
But maybe I’m just weird…