[mattm]

This is the answer. There is no better period. There is better depending on the context. Can you imagine having all your conversations with your spouse in front of all your co workers?

Their company size is only 25 people. I doubt they will be giving the same advice if their company grows to 200+ people.

[Trasmatta]

Exactly. The advice doesn't quite scale. I find the better approach is: if this feels like a question that the wider team would benefit from seeing and contributing to, post it in a public channel. If not, then message it privately. Use your own discretion.

At some point you should trust your team to be adults, and to make the best choice for the situation.