Gating lead magnets with an email is common because it feels less personal for most users. Many people are willing to give their email in exchange for something useful. Asking for a mobile number can still work, but it might reduce how many people sign up because some are more careful with phone numbers. If the offer is strong enough, like free credits or something that feels valuable, asking for a phone number can still bring in good results. But if the lead magnet is something simple, it might be better to just ask for an email to keep the process smooth. It's about balancing how much value you're offering with what you ask in return. If the goal is to collect quality leads for follow-up, both methods can work when used right. What has worked better in your own testing or what are you thinking of trying?