Meeting a woman for a date on a street corner is always a bad idea, no matter how long you've known her. Here is a short list of the reasons why:
1. Women are terrible at directions. There is a very good chance you'll end up on different corners, and the date will therefore either abort or start off horribly.
2. If she is attractive, she'll have to deal with guys hitting on her while she waits for you (if she's there first).
3. If you're there first, you'll be wasting your time hanging out on a street corner (is that how/where you want to spend your time?). You will likely not be able to pass the time fending off women who will be flirting with you. More likely, as a single guy hanging out on a corner for an extended time, you'll be assumed to be a loser, homeless, or worse.
4. It may be loud, and hard to hear your phone if you need to call each other (if one of you is late).
5. It could rain/snow/etc.
6. She will likely resent that you've put her to any inconvenience, and meeting someone at any location that isn't familiar is an inconvenience.
As to your main point, it may be that it is not cost effective or an effective use of time to date civilians compared to seeing SPs. However, that would depend entirely on how much fun you have on your dates, and how much you can suspend your hold on reality while you're with an SP. In other words, it's a crapshoot which is the better deal/experience. In my own personal experience, most first dates/early dates don't turn out to be worthwhile. Also, most sessions with SPs turn out not to be worthwhile.
But no one ever told me to expect life to be perfect, so I accept the bad with the good.