To be fair Statutory Paternity Pay (SPP) is paid at the same rate of Statutory Maternity Pay (SMP) which currently is £138.18 per week (or 90% of your average weekly earnings if this is less). The only difference is that for the first six weeks of SMP it's paid at 90% of the woman's average weekly earnings rather than dropping straight to the £138.18.
Though I'm not sure I'd say it was useless as having two extra weeks of leave when you might well need as much annual leave as possible later to deal with the new baby is surely a nice thing to have!
Also everyone's finances are different. If you're on a reasonable salary (and therefore probably have quite a high mortgage/rent payment and plenty of other high costs items perhaps a full fat sky package) then suffering such a major drop would hurt and could make it hard to cope (though if that is the case some emergency savings or insurance might be wise to provide cover if something happens to that salary like redundancy or long-term illness). But there will be other people who either have low bills or are on a low wage so adjusting for a short period to a bit less money might be possible.
It's complicated and I'm not sure you can just dismiss it as useless in every circumstance.
That being said I do think that's unfair that SPP doesn't pay at 90% of your average weekly earnings for the two weeks and making that change wouldn't be a massive cost for employers (most can surely cope without an employee for two weeks) but would have a big positive impact for parents. Plus whatever happened to equal pay
