There really is no point disclosing your phone number since 90% of the interaction is done through the app. Most sensible, level-headed people will not have a problem with just using the app. People will always demand your phone number and address then pull a no show. That would be one good reason not to give out your phone number or address. Most of us have done it.
Please think twice about giving out any personal information to buyers or sellers. Yes, that includes phone numbers. We highly recommend against it. @clintonkeep and @FearLess are right, and everything you need is built within the app. If you have any suggestions for features you'd like to see us build and why, let us know so we can learn from you and note it down!