Conversely 1:10000 is so close to 0:10000 that you might as well just leave it on the Bitcoin blockchain. The benefit of not doing so would be negligible.
No. Makes no sense whatsoever.
True, the choice of settlement platform is leveraged 10,000:1 in this scenario for the transacting party. As such, it probably does not much matter to the transaction party whether the underlying settlement platform is Bitcoin or a vastly cheaper alt.
It certainly does matter to the customer. Customers will chose a BTC LN over an alt LN for the same reasons they (usually) choose BTC over alts. Those are well known so I will not repeat them.
Regarding the idea of a completely uncollateralized fiat payment network, I already answered that, twice. If people want that they will just use existing fiat networks. LN offers nothing special to them at all (nor does Bitcoin in any form, or alts).
Yeah... about that post... sorry... I didn't realize I was doubling (long boring story).
But I still think you put too much faith in the purchaser.