Only that he'll end up needing a 25kg bag of multifinish. Filler is easier to work with dries faster TX110 doesn't shrink much and can be sponged off and is likely closer to the finished colour.
But on a building site with 20 chases to fill , yes multi finish would be a good choice.
Ah sorry I actually meant, was there an advantage to use;
bonding to fill the majority of the volume then filler for the last 3mm
Vs
Bonding to fill the majority of the volume then multi finish for the final 3mm?