I just want to say that if Poke Pelago is the only way to get Shards, Hyper Training isn't going to be a viable method of.. anything really. Hyper training legendaries occasionally will be about it.
Bottle Caps cost 30 Shards of the same color, and a day of mining them on Pelago gets you about 4, and they usually aren't the same color. Spending Beans to speed up the process can get you about 8 Shards per 24 hours, the extra items you get for spending Beans on top of the faster mine time are non-Shards it seems. This means that you're looking at potentially 4 Bottle Caps every 2 weeks.
This can remedy not having good IV's on Ultra Beast and Legendaries (assuming you got good natures on them) and it can give speed to select HP Fire mons or whatever, but it definitely does not replace breeding with an accessible system that levels the playing field and gets rid of the need for hacking to stay competitive ─ if anything it's a gruelingly slow buffer to fix bad IV's on things with good natures. Being able to Hyper Train is a rare occasion and it doesn't fix the issue of bad natures on legendaries. New players getting into competitive play will still have to spend money on a new game to re-catch the legendaries they didn't know they had to reset for natures, received hacked legendaries from other players, or hack themselves.
Of course aside form natures most of this goes away if there is a way to quickly farm Shards that I just haven't discovered yet, so feel free to tell me to settle down if that's the case. It's also worth noting that a new player can take his or her UB's and presumably SOS chained mons and put a dent in the Battle Tree in order to get the items locked behind the BP grind, as well as the fact that a surprising amount of competitive items (Focus Sash, Life Orb, etc) are actually located on the map and not BP-only items.