CoO itself can be used to sense auras in the vicinity, so if your body can’t be seen, in theory, your aura can still be detected. Plus with the introduction of Ryuuou we know that ordinarily, vasts amounts of Ryuuou/Haki surround the body. So, unless you can get rid of Ryuuou/Haki outside the body, detection should be possible with CoO. How easily this can be done however, remains to be seen. P1 like Oven & Daifuku should be capable of using CoA/CoO given his position in Kaidou’s crew, but Sanji’s invisibility proved a tad to difficult for him to handle). So could be that you have to be very proficient at CoO to be able to counter invisibility & that P1 just wasn’t proficient enough at it (i.e. This is diverting a bit lolz, but let’s take Kizaru as an example, being able to use CoO doesn’t automatically allow you to be able to counter his ability, however very proficient users of CoO can, according to his Vivre card IIRC.)
That said, Shiryu states that it is a very useful ability, which is true, but given a high level CoO practitioner should be able to counter it, it makes you wonder how useful it actually is on a high level and the answer to that I think is that it isn’t, by itself at least. However if you are able to remove/hide/disperse the Ryuuou/Haki that surrounds your body then unless your opponent has FS which makes him/her see actions before they happen, then you should have his or her number. I reckon the above technique is possible, considering the Ryuuou/Haki that surrounds the body can be manipulated by using it as a barrier of sorts like Sentomaru/Rayleigh/Hyou or by transferring it into your opponents body to destroy it from the inside like Luffy/Rayleigh. Raizou prolly used said application on Zou when he vanished & no one could sense him. Shiryu is most likely from Wano, so like Raizou (potentially), he could be capable of such a technique.
