It's depend to what CC TLDs. If it is .co.uk or .uk, NNN is hard to sell. British people not buying .co.uk and .uk in Number. So even you use paid auction, and it gets more exposure, mostly will not sell.
If it is .de, .co, .us, paid auction surely improve exposure. How much the range, depend on the CC TLDs. For example NNN.de sells higher than NNN.us or NNN.co.
You can check the history of NNN CC TLDs on Namebio. Cheers..