I’m not a big business card person, but when I go to conferences—such as the upcoming writers conference I’m attending next week—I will carry two business cards. Both include my private email, but only one has my direct phone number.
I think this added degree of flexibility is important, especially in this age of phone spam.
I am happy to give most people I want to connect with private email access to me, but my phone number gives someone 24-7 access to me—to my physical person—and for that level of connection I have a high bar, especially at a time when contact lists are easily shared and embedded in third-party systems.