Yes, it's important to point out to students once during their schooling that there are some other words that mean "said" which might, on rare occasion, be usefully employed. But it is not helpful to insist on changing every "said" in an actual piece of writing (as opposed to the 12 example sentences on that one worksheet). If your English teachers had a thing about "said" it's because they read that one lesson and didn't understand that it was intended as a tool to add to the writing toolbox, not a rule to be slavishly enforced. In fact, it probably indicates that your English teacher wasn't even reading stories because if you look at actual writing, there are way more "said"s than their alternatives.
Don't think of "said" as a word: it's punctuation. Just like commas and periods, said is completely invisible to readers with Grade 5 literacy and above (i.e., your readers unless you're writing for beginning readers). Replacing said with any other word introduces stage directions into the dialog. Sometimes one needs stage directions, but providing stage directions every line of dialog drives readers to distraction.
First, stage directions are usually redundant:
"I hate you!" he shouted.
Really? You had to tell us he shouted that? The words "hate you" and the exclamation point weren't sufficient, you had to step in over the reader's shoulder and whisper into their ear, "this line of dialog is shouted"? Dialog, if well written, should be self-explanatory. We don't even need a "said" here, because unless there three different couples all talking at the same time, it's usually pretty clear who is yelling at whom.
There are three problems with replacing the invisible said with stage directions.
First, unnecessary stage directions are words that could be cut to tighten the writing to speed the pacing and so increase the tension and immediacy of the scene. "I hate you!" doesn't usually need any explanation. You can just move on immediately to the next piece of action or to the response:
"I hate you!" Grabbing the gun off the table, he pulled the trigger. (No dialog tag required.)
"I hate you!"
"I hate you more, you bastard!" (No dialog tags required.)
Second, said replacements are often a sign the author is over-controlling, trying to dictate to the reader every tiny detail and nuance. Insisting the reader read the scene exactly as you saw it in your head is self-indulgent and alienating. The reader has to be allowed to bring something to the page, just like the play director has to have some room to interpret a script. Once you've written the scene, it's not yours anymore: the reader gets to remember the time their mom/lover/neighbour said "I hate you!" and bring all that emotional baggage to your scene, to relive those emotions in your scene—which makes your scene way better than you wrote it. That won't work if you insisted "he shouted" instead of "he growled" which is what it was for them.
Third, too many obvious stage directions (like "he shouted") could be received by at least some readers as insulting to their intelligence. Not a reaction you want!
Therefore: save "said" replacements for when you need them.
For example, if the character is saying something in an unexpected way, then a "said" replacement can really improve a line of dialog:
- "I hate you!" he whispered.
Oh yeah, we needed that "whispered", because it goes against the expectation of the exclamation mark, which is way creepier than some guy shouting it. People yell their emotions all the time and don't necessarily mean it literally; a covert, whispered threat can be significantly more sinister. So sometimes we need the stage directions.
Sometimes we need a dialog tag of "John growled" because even if the tone is obvious, the speaker isn't and "said" would be discordant with the emotion being expressed.
And sometimes, yes, we need to break up 200 "said" dialog tags with something different. But the use of said replacements has to be deliberate and sparing.
Too many "said" replacements is called "said bookism" because it usually feels like the author is trying too hard to elevate their writing. Said is indeed elementary, but replacing every "said" quickly comes across as pompous and tedious. So, choose carefully.