Good observations.
However, I cannot think of a better example/definition of pointless excess, than everything that is made by Porsche or any other exotic car manufacturer for that matter. Tesla is really not much different in that regard. Bottom line is.... there is a big demand/market for pointless excess. Sorry to say, but if you own a Model 3 (even the base trim), then you fall into that category of buying something that is a pointless excess. If the goal it to own a good practical EV, then why not just get a Chevy Bolt or Nissan Leaf? Both of these are fine vehicles, very practical, plenty fast and considerably less expensive/excessive than a Tesla.
To me, Tesla does not make “luxury” vehicles (in terms of premium materials and plush interiors). Instead, I view Tesla as making ultra-high performance vehicles with just slightly above average interiors. Even the interior of their most expensive Model S is not that great/luxurious IMO. However, that is OK with me, because I purchased knowing that what I’m really paying for is performance and not “luxury”. To be honest, the interior of my Model 3 is plenty comfortable & luxurious for me. Could it be better? Absolutely. But, it’s not necessary (for me).
The only area where I think Tesla really needs to improve is quality control in their assembly line (better control of panel gaps, missing clips, loose wiring harnesses, etc... and perhaps paint). If Tesla does end up offering a Plaid Model 3, I would expect them to also have a more refined interior as well. However, even if they don’t, I’m OK with that because of the huge gain in acceleration & speed (and probably range) that come with a “Plaid” trim. For those who value luxury over performance, expect/demand a ultra-plush interior when spending $75-100K on a vehicle, or are simply more practical in nature,... then a Plaid Model 3 is probably not for them.
Finally, to answer your question about why anyone would feel the need to get the Plaid+ S over the standard Plaid S, I think it would be for the huge increase in range (over 520 miles for the Plaid+ versus “just” 390 miles for the standard Plaid).
Of course nothing has been finalized yet, but at least right now, Tesla is showing nearly identical speed & acceleration numbers for the Plaid and Plaid+ S. For 0-60 acceleration, they show “1.99 sec” for the Plaid and “< 1.99 sec” for the Plaid+.
Looks like there will be around 100 hp difference between the Plaid S (1020 hp) and Plaid+ S (1100+ hp). If that holds true, then 100hp should not significantly improve that 1.99 sec 0-60 time. We shall see!!