Its 100% necessary if I want to be installing standard Linux applications which by default install to /usr (among other places, most of which are located in the root partition). Half the reason I bought this device is because it is compatible with 18,000 debian packages that are out there.

I must say - the default file system setup on the N900 is by far its worst feature. I can understand why it is setup the way it is for the basic phone user - but it should have an option for those who want to tinker to readjust the partitions to their pleasure IMO

~Jeff