It's placebo (unless you mean 24/96 vs 16/44.1 of the same vinyl rip in which case it's still probably placebo). DVDA or SACD sources are always preferable.
Well each time you play a vinyl record the needle damages it, so by recording the first play at 24bit you keep all the information, albeit digitized. Only an unplayed record can be turned into a 24bit rip.
Not exactly. You're right that an LP degrades on every play (less so with better equipment and storage practices) but you're wrong in that you're keeping all the information. The analog->digital conversion is quantizing the analog soundwave into digital form, which completely benefits the so called advantage of vinyl: the completely analog signal chain.
Throw in the fact that many modern LPs are recorded digitally (and certainly mixed/mastered digitally) and many modern LPs are directly sourced from the 16/44.1 CD mastering, and you have a boatload of fail in most cases. By the time the sound is actually coming out of your speakers it's been transcoded multiple times from analog to digital.
Regarding the 24bit part, that's not exactly true. 24bit sound increases the dynamic range of the recordings, but most LPs probably don't have the dynamic range to make use of those extra bits, and if they do it's not necessarily completely degraded on the first play. Hell, many LPs, especially older ones probably don't even have the dynamic range to fill a 16bit file. And even if the LP is superbly pressed and mastered, people doing vinyl rips online are often teenagers using shitty equipment that cost a few hundred dollars all told, or even worse, a USB turntable.
The only time a vinyl rip is better is if the mastering is significantly better than its CD counterpart (this isn't always the case, you can brickwall a vinyl master as well), or of course if there is no CD counterpart. Otherwise you're better off buying the LP yourself and downloading the CD sourced FLACs.
tl;dr Vinyl rips are mostly useless, especially 24bit rips.
Edit: Also "Vinyls" is not a word. Every time I see that I die a little inside
