Well, losing 1kwh in a 300 foot run is bad, losing it in a nema 15-40 is a fire. So... there are degrees of bad...
Lots of this math is similar to "should I buy my cable modem?" -- depending on an complex array of short and long term costs and savings, it may or may not make sense. Similarly, investing $200 for N% improvement in charging vs investing $5000 for N*2 % improvement depends on lots of factors.
A long thin cable with lots of heat loss may be fine if the alternative is trenching through your driveway...