Attendance at the JW memorial benefits no one except boosting the pride of the governing body and their hapless followers.
The objective seems to be to get as many people who can't think for themselves along to one specific meeting. It's a pointless exercise except to be able to brag. Why would anyone else be impressed with the numbers attending? JWs never miss an opportunity to pat themselves on the back.
Why is it wrong? Because the memorial is just another superstition with its roots in folk belief. In fact the "last supper" was borrowed directly from Mithraism from the sacrificial death of the saviour Mithra who was commemorated once a year at the spring equinox by the use of symbolic cakes and wine. And (dare I mention it again) that Mithraism found spiritual strength in the memorial story because human sacrifice was the most potent tribal magic available.
By the time of the Roman empire, they had forbidden literal human sacrifice so religious rituals continued the sentiments of the sacrifice in symbol only, and this was what Christianity borrowed from Mithraism for its own use. Jesus' death was just a cut and paste job. Bamboozle the gullible with 'holy' superstitions and it's only the priesthood (read JW governing body) who truly benefit.