But more often it's useless. If you're trying to communicate with someone who's clearly not using the dictionary definition, it's probably only good for detangling their actual usage, aka meta-argument. In this case, certainly, you did not address the substance of their argument with your objection about the definition of "profit".
But you're going to "well actually" someone's comment based on the second definition when they're using the first, rather than actually communicate. Makes perfect sense.
I've always understood how a dictionary entry can have multiple meanings. You're the one who started off citing "the" dictionary definition.
Whereas my point since the start has been that the dictionary definition is barely relevant to good-faith communication, which tries to understand what the other person means and engage with that. Even if they're using the number 1 definition, and you'd rather use number 2.
Also, I don't know what dictionary you're looking at. These all seem pretty money-focused to me. https://www.oxfordlearnersdictionaries.com/us/definition/eng... https://dictionary.cambridge.org/us/dictionary/english/profi... https://www.merriam-webster.com/dictionary/profit