Trading VS earning and such


I’ve gotten here in a weird turn of events.
First I’ve discovered sweatcoin by sheer luck. Second, I stumbled onto sweatcoin traders.
And then I stumbled into the sweatcoin shop thing, which I believe should be called “SweatShop”.
Come on, guys, it’s not like you get another reasonable… reason… to not do this!

So there are sweatcoin traders.
A marathon offer offers an iPhone XS in return for 20k sweatcoin.
The offer states the sweatcoin must be earned by me.
Is there indeed a mechanism to keep track of how much I’ve walked vs how much I had sent to me?
Which well does it deplete first?
If I turn into a trader, DO manage to gather 20k sweatcoin for… whatever comes next… am I screwed for turning 100% trader or does it keep track of how much I walk?