ehhh idk I get the number fairly quickly. I'd rather move the conversation off the app asap because it gives you an identity. You move from being just another hinge convo to being "Tommy Lee Jones" in her phone(if she finds you attractive and liked the convo she'll save your # immediately) and If they're willing to meet you, they're willing to give you their number LOL. Just the way I see. Besides it helps with logistics I.e of someone is running late, etc. Some of these chics do not have notifications on for the app too so you might be waiting for a reply where as a nikka like me is texting her or facetiming her already
Next time you suggest a date and they accept immediately ask for the number right after.
For me I say
"Id like to see you. We should grab a drink sometime. What's your schedule like?"
That gives them an out to say "I'm busy, I don't have much time off" or some shyt but that hasn't happened yet.
They respond something like "I'm free weekends and after work usually 6pm"
Me: great, I'm free Friday afternoon I know a good spot in blah blah blah we could go to. What's your number?
Them: *number*
Then we text moving forward.
Hasn't failed me yet.