I was told it's a waste of time, but maybe somebody else that's done it can chime in.
Not as much as a waste of time as other things. Its def cool and once you're there i would reccomend. Not that you should expect to see anything inside. Just a narrow claustrophobic passageway.
While researching my trip, my friend found a different pyramid, that is not so touristy that still has some stuff inside but I cant find it now...
ETA it may have been Saqqara...but I really dont remember. unfortunately our time in CAiro was extremely limited