(also let me clarify, that I have nothing against people saying there are tiny fees with Bitcoin... It's not wrong to say that upfront, I just think either way is fine and it often depends on the context of the conversation and the audience)
The fees are so low that people don't believe you. A true "First World Problem" with Bitcoin.
Saying "the transaction fee is less than a penny" impresses people, and leaves them in a positive frame of mind.
Saying "it's free" is dishonest. It makes people defensive and leaves them wondering what the catch is.
"Less than a penny" is currently true (at U$20, the suggested fee becomes exactly 1 penny), fast and impressive. I'll stick with that for a start.
Even if the fees are small now... If any significant portion of any countries economy was transacting then the fees would grow quite large to keep the networks new load viable.
I agree. Transaction fees are crucial for the long term viability of Bitcoin's deflationary aspect. People have to understand from the beginning that the fees are designed to sustain the blockchain later.
The fee may be small, but its importance to understand Bitcoin is not.