yes it is useful, but not mandatory, none of the skills a barb can take are mandatory (ie help their main focus in life which is max dps) so any skill you take which has it's use is simply fluff and for your playstyle, not everyone wants to mash intimidate every 6 seconds or ever for that matter, and not everyone wants to umd raise the dead or heal themselves. personally as a 20 barb i had max imtim and umd as there were times id use both etc... but that is my personal playstyle, ill still argue they are not necessary however.