“You get either or whatever fits your toilet. It’s not specifically for sink only.”
Incorrect.
The cup plunger is designed to fit over drains on flat surfaces, while flanged plungers are designed to fit inside the outtake valves of toilets.
“Some toilets use the normal “sink” plunger because the exit opening is too large for the “toilet” marked style”.
This is also wrong because:
The flange is as wide as a cup plunger for sinks anyway, so a sink plunger won’t work if a toilet outtake is too wide for a toilet plunger, and
the toilet plunger is made to fit inside the outtake of the toilet, not over the mouth of the drain like a cup plunger.
they are completely different designs and have different use-cases that you will only give you and others more trouble and mess for by not knowing and spreading misinformation.