We specifically designed the Emigdio Series chair to have a slightly higher/wider seat position for that very reason. Many of us here are over 6ft tall & find the seat position to be comfortable. Keep in mind that the seat is still lower than your "standard sized" camping chair due to the compact design.
The chairs will do just fine at the beach. They do great on the hard pack. In dry sand they will sink slightly due to the leg design. If you don't mind a slightly lower seat profile they will work great.