^^^
For me, adding "lead-in" measures will help in song arrangement in the Track View. Some of my external, hardware synthesizers need proper "lead-in" measures for their arpeggios, delays, and general timing to work right. Therefore, in order to solve this issue, I must add one or more blank measures starting at 1:00:000. This, in turn, disrupts the subsequent, numerical-sequence of measures which I would use to help build a song, e.g. 4 measures from 1:00:000 to 4:00:000, 8 measures from 4:00:000 to 12:000:000, etc.
There is a work around, and that is to build a "template" track. In this track, I create brightly colored, "dummy" MIDI clips that are easily seen. I make 2-bar, 4-bar, and 8-bar clips...all with different colors. I then use these clips to keep my timing right in song creation.
I think the lead-in measure (i.e. negative measures) is mostly beneficial to the folks who use outboard gear.