While this is evidence that the horse can gait, it doesn't seem like much evidence for the horse being able to reach the leg angle/height requirement for the saddle seat disciplines like English and Park Pleasure. Trail and Country Pleasure likely could accept these horses to the highest (Trail) or decently high (Country) level, but I'd be hesitant about their performance in the others. I assume this is not about levels in fine harness or adding them to speed racking, but it is unclear to me which disciplines the member intended.
It may be helpful to note that our Saddle Seat disciplines are not "gaited shows", but saddle seat shows; a slight, but important distinction when discussing the differences within that group of disciplines and what a breed's potential is. For example, Arabians are not gaited, but perform excellent in saddle seat because of their range of leg movement. The only saddle seat discipline with the requirement of a horse being able to gait is Speed Racking as a horse must be able to perform a rack (or a gait very similar to a rack like the tölt of Icelandics or revaal of Indo-Pakistani breeds) and perform it at a high speed. The rest need evidence of the breed's use/potential use (such as it performing in a similar type of discipline under a different native practice depending on the country). I don't see that in these examples, especially when discussing the high-stepping of something like Park Pleasure. But I could see the addition for something more like Trail Pleasure.