The problem is not one of data, the problem is your friends. Specifically, the choices they have made have drastically reduced their available candidate pool. There are numerous dating sites that use data to attempt to find the perfect match – like eHarmony, and OKCupid – but they provide no more success than any other dating site, in fact I’d suggest that they’re even less successful.
Dating is a numbers game, successful dating involves determining your known requirements and then meeting as many people as possible that meet those requirements until you find the person who meets your known requirements and your unknown requirements and you meet theirs. A good match isn’t someone who shares your interests, it’s someone with a compatible personality.
Dating gets harder as you get older: your candidate pool is shrinking as prospects are coupling up with others, you become more invested in your life and career, you become less and less flexible and more and more married to your way of doing things… and so to date successfully in your 30s (and beyond) you must be willing to put the effort in. An app that uses data (whether it’s financial or a playlist of your favourite music) is at a disadvantage because users see it as an opportunity to be less invested in the process but in reality it requires the opposite, they need to be more invested in the process.
Personally I think using financial data is an interesting prospect because it does allow you to profile someone quite successfully however I don’t believe that addresses the underlying problem with this model of online dating… and that’s before we even consider the complexities involved in encouraging someone to hand over their financial data to a dating site.
Tinder (and equivalent) have proven over the last few years that the money in online dating is enabling matches, more matches is more money. Your best bet is to build out your system, patent it and then sell it to a company like eHarmony – or if you can’t protect it from being copied, build a mature enough product that it makes sense for it to be acquired rather than copied.
If you want to help your friends, tell them to stop being so precious. If they are finding current dating systems difficult, then they’re going to find any dating system difficult. They need to realise that they’re at a disadvantage dating at this time in their life, and so they need to really invest their time into it, in the same way they invest their time into their careers. If they’re meeting people who “[…] aren’t what [they were] expecting […]” then they’re not putting the effort in that is required.
When thinking about online dating it’s important to consider it compared to traditional dating: you meet someone in a bar, you know very little about them, and you’re immediately willing to invest hours of your time into talking to them and enjoying their company and learning all about them and their life, just based on that little piece of them you see that interests you… and yet online, it’s the opposite, unless someone is “perfect” and satisfies our exhaustive criteria it’s a left-swipe… and even if we do match, we exchange a few messages and half-heartedly try to arrange a date… online dating tricks people, they think “I see more people so I can put less effort in per person” when it should be the opposite, online dating requires even more effort than in person. If your friends put as much effort into online dating as they did the interactions they have through traditional dating methods they would be a lot more successful.
Anyway, I don’t mean to discourage: you should build it anyway, launch it, see what happens, maybe you can change the way people date… but dating is an extremely competitive market so don’t bet your house on it.