There are a few reasons why recruiters always want a phone call instead of just providing the information up front.
One is that they're salespeople and they are treating recruiting like selling you a job, and they think it's easier to sell you something when they are actually speaking to you. This is a bit silly because a new job isn't something someone just takes on a whim and if they need to sell it to you then it's probably not a good fit, but recruitment is a competitive industry where people are pressured into meeting targets, so you end up with this kind of mindset.
Another reason is that they might be fishing for information. They'll pretend they have a job you might be interested in but they'll keep it vague because they actually just want to get you on a call so they can ask you questions. They might ask about your current employer or ask about other places you've interviewed, because they want some information that will give them a foot in the door with an employer who might have vacancies they can feed candidates into. You should, of course, never tell a recruiter where else you are interviewing, because they'll try to put in their own candidates in competition with you!
A third possibility is that they see you as being someone that they might be able to place into a job in future. They don't necessarily see that happening right now, but they want to get you into a conversation so they can find out more about you and more what would interest you so they can target you in future if something relevant comes up.
In each of these cases, speaking to a recruiter is pretty much a waste of your time. If they have a job they're trying to fill and they genuinely think you're a good match then they'll provide you with some information ahead of a call.
My rule of thumb for recruiters is if I think they're wasting my time, they probably are. I always ask for salary, location and job description up front before agreeing to a call and if they can't provide that then I ignore them. You'd be amazed how many just ignore what I've asked for and try to schedule a call though.
A not uncommon tactic is to pretend that they've had prior contact with you and they're following something up. For example, in the last week, I've had one recruiter email me requesting my phone number to "discuss the application I'd made" (I hadn't). And another one gave me quite a detailed story about how since we've spoken last week (we didn't) he's been in contact with the hiring manager and he thinks my [experience on my LinkedIn profile] is a great match.