You're probably going to have trouble with the final (utility knife) cutting of the parts. Unless your customer is very careful they run the risk of tearing the veneer of the plywood as they "punch" out the parts
Additionally what a pain to have to cut out the entire perimiter of the parts by hand with a knife. With tabs just use a Jig saw to cut the final tab and then only have to sand the 1" area where the tab was.
Just my thoughts.