Multi-server adminsitration is useful for situation where your environment meets the following criteria:
1. The same job must run on more than one SQL Server.
2. The job can/should run at the same time on each SQL Server.
3. In the case of jobs that access the file system, the partition layout each SQL Server sees is the same, e.g. D:\. Problems are presented if, for instance, you back up Master to \\Server\Share\Master.BAK because while all of the servers may see this location, all of the servers will be trying to back up to the same file at the same time, and that won't work.
This sort of thing worked great for me at my previous position. I had 4 SQL servers at different offices that backed up to their local disks, had the same databases on them, and I had set up the partition's directory structure the same. All of my backup jobs could run at the same time and dump the same files to the same location, relative to the servr where it ran.
In my current position, while most directory structures are the same, I manage different databases on each server and not much about them is the same, except for the system DBs, Master Model, and MSDB. I can use an MSX job for backing up those if I want.
Now, if you have a job that is smart enough to determine the relative parameters (that need to be different for each server) at run time, you may find value in an MSX job also.
Chris