I have absolutely no interest in supplying my phone number to outlook. It will not increase my security, rather it will increase the amount of personal information about myself which can be disseminated online and increases the number of ways an individual, company or group will be able to target me.
I want to continue using outlook (despite the unhelpful changes in format foisted upon those who were happy with hotmail) but I refuse to give any further personal details, otherwise I will have to leave outlook and have all my e-mails redirected.