You need some sort of cryptocurrency for this as
microtransactions don't really work in the legacy
system.
Also by using their own token they can boot strap
the ecosystem cheaply as they can mint the tokens
themselves with the value accruing later after
network participants are onboarded and transacting.
Projects like Augur and MakerDAO must have their own token or they wouldn't work at all. Augur and MakerDAO have healthy token economics.
I'm not an expert on BAT token economics, but I believe Brave would have been much better off using ETH itself or a stablecoin. afaik Brave's microtransactions don't require BAT to work and that makes BAT a bad token.
Why?
My personal favorite example is:
https://www.stellar.org/papers/stellar-consensus-protocol.pd...
Transactions take a few seconds, 10000 transactions per $.01 as well as no mining for coins so it is not a bad coin for climate change compared to say Bitcoin and the mining farms.
Just my $0.02
What you describe above has to be weighed against loss of value for holding until accumulating enough to trade for $ no, as well as general fees associated with trading for $ generally?
Else what really is the point, if maintaining the value transferred isn't possible?
For example, see https://comingsoon.idex.io/ which is state of the art.
The Lightning Network allows microtransactions on the bitcoin blockchain quickly and cheaply; since it went into production last year, over 10,000 nodes have joined and there's over $7 million in network liquidity: https://1ml.com