vilas I'm a great fan of not burning more fuel than needed. Tried F3 when it made sense, now and then.
Wise opinions above already, it's a very hard task to calculate whether or not will F3 bring real fuel savings (extended taxi time), or burn more money on reversers use et al. The opinion I like the most, is to educate the pilot pool and give them the option. Not to force it into standard practice.
There is one case I know of, where it would be a good and reasonable STANDARD option, In LIMC/MXP, 98 % of the time the landing direction is northbound. A large LoCo using predominantly A319s is based in the northern terminal T2
https://www.google.com/maps/search/M.../data=!3m1!1e3. Plain to see, using F3, idle REV, no ABRK will get you to the gate quickest, cheapest and greenest.
In VEIM the taxi configuration looks inviting. My first choice would be NO, not as
a standard. Mostly due to steeper glide, crew proficiency must be considered. As an educated choice, why not, I would happily let the FO fly it.
Check Airman One minute taxi time burns 11 kgs of fuel (+2 for APU), completely no strings attached. Engine-hours also a factor if. The alleged F3 savings on approach are 6-8 kgs, and people are discussing the latter.