I don't know what the PH Kyoto onsen set up will be like, but Suiran only offers onsen access in the spa (you need to get a treatment to use it) and I believe the Presidential Suite (and possibly other suites?) also has a private open-air onsen, so its not readily accessible to all guests. Of course, Suiran has no pool either, but you wouldn't expect one there anyway. It also has a super tiny fitness room, which I wouldn't have expected either. That said, I'd say its main draws are its location and temple-like grounds. Frankly, the standard rooms are below what I would expect from a Category 8 hotel. Other than that, it's perfectly charming hybrid ryokan-hotel. If the PH Kyoto can offer an onsen that is accessible to all guest for free or at a nominal cost, that's a significant amenity, since Japanese guests are far more likely to use it than a pool.