In order to make that critical high-value transaction you are going to have to move a high volume of BTC to the sidechain
Unless you buy BTC on the sidechain to start with. For example, they spend BTC to buy mining hardware to mine anonymously. Isn't that how you got your XMR.
And anonymity is not likely the only feature that can appeal to slower transactions from the high valued demographic.
You can see every possible feature now? Wow you are omniscient.
And slow transfers between Core and side chains for high valued is not the only case, as I pointed out upthread.