Truth is, just about any phone can be made wireless charging capable, but The voltages and current rates coming off of those pads are in ranges far outside of what the battery can effectively use to charge, so it's the bridge charging circuit that has to be designed to accept the voltages and current rates from the charging pad and convert them to usable and appropriate voltages and current for the battery. It appears that Samsung has built that key circuitry right into the phone and conveniently placed two terminals immediately above the battery, so all that is required is essentially an antenna - an electric coil that is printed onto a thin film and ends in two contacts that match up with those in the phone's case where the input terminals for the wireless charging are located. The whole thing is probably not much thicker than a business or credit card, so it fits nicely inside the curve of the cover.
In contrast, other phones which are not "wireless charging capable" out of the box, instead require the unique bridge circuit to be built into the cover or case, or even into a completely replaced battery and cover combination, to achieve the same goal. Even though there may be "terminals" in the other phones on the motherboard that tie to the battery and/or charger, the question is whether the circuitry on the motherboard is equipped with the voltage conversion circuitry to accept those different voltages and step them down to the charging voltages required by the battery. I think the likelihood is those terminals are not leading to a voltage step-down circuit but instead directly to the charging circuitry - in other words terminals to TEST the circuitry's functionality, NOT to charge from.