Thanks op for bringing it to light. I think Satoshi wanted to boost adoption this way, and it was probably a good call.
I doubt that satoshi ever used a web wallet.
Many others who did arguably increased the value of coins of those who did not !
Something, something lost down the side of the proverbial digital sofa ...
Probably not, but since Bitcoin was still very new, Satoshi probably wanted to find a way of making Bitcoin more accessible, so that people who are not techy could start using them. And I suppose the amount to store there should depend on its purchasing power and on how much (as Ucy pointed out) some money is worth to a particular person relative to this person's capital. Pocket money in BTC in 2020 and in 2010 are to very different things.