The implications of rounding down are more applicable to win and place betting than exotic betting.
If a dividend was exactly, $2.19 it rounds down to $2.10, for those that place bet shorties at $1.50 etc, an additional couple of dollars in the pool bet on that runner could tip a dividend from $1.50 to $1.40 if it is already hovering around $1.50.
In percentage terms, that loss of 10 cents from $1.50 to $1.40 or 9 cents from $2.19 to $2.10 are massive, however if a Trifecta dividend was reduced from $423.19 to $423,10 it is marginal, however, the deduction rates on trifectas, as are all exotics bets, far in excess of the deduction rates on win and place.
For that reason alone the kickbacks offered on exotics are greater than those offered on win and place betting. Mere mortals, not receiving kickbacks, can please themselves whether they are subject to rounding down on win and place betting or endure the higher takeout rates on exotics.
A bit like a doubled headed coin..it is difficult to win if you continue to back tails.