Hi Camila,
Many guys ask for a snapchat or instagram after meeting someone on a dating app because it gives them an opportunity to get to know the person without having to exchange phone numbers.
Those platforms enable them to get a preview of what the person’s life and personality is like before making a decision on whether they would like to go further.
In this day and age, for a lot of guys, the phone number is a means to set up a date, not necessarily a means to get to know someone better. Yes, that goes for guys in their 30s as well.