As written HPS is effectively once per battle, while NV is PB per day. For HPS you can do the camo at the start of the day and then after every battle (or every one you hide in) and you have a use on of HPS on tap. RAW you can be in plain sight and in the middle of a fight and press yourself up against something and hide. You just can't do it more than once per fight because of the 1 minute time. RAW you can literally be in the middle of melee and move up to a wall hide right there. If you rope this together with PWT you can hide against any verticle surface and have a whopping +20 to your hide check. In this respect it is better than invisibility, which only gives you advantage on hide checks. You can also hide from creatures using blindsight or truesight with HPS, while invisibility does nothing against them.
RAW there is nothing about the DM deciding if the terrain is appropriate, only that you must have access to the materials and that what you hide against needs to be as tall and wide as you are and it has to be solid. I realize there is some judgement in the materials part, but if your DM is going to rule you can not find those materials, it is safe to assume he is not going to let you use a more powerful version of it either.
NV is more powerful (arguably OP) because you can do it over and over again as a BA in a single fight.
Unless your race is some sort of chameloen, it is hard to imagine a non-magical feature that would not thematically require putting on camo.
RAW there is nothing about the DM deciding if the terrain is appropriate, only that you must have access to the materials and that what you hide against needs to be as tall and wide as you are and it has to be solid. I realize there is some judgement in the materials part, but if your DM is going to rule you can not find those materials, it is safe to assume he is not going to let you use a more powerful version of it either.
NV is more powerful (arguably OP) because you can do it over and over again as a BA in a single fight.
Unless your race is some sort of chameloen, it is hard to imagine a non-magical feature that would not thematically require putting on camo.