You literally just said "He's a 3 star WR aka possession WR period." Last time I checked, Smith and Holmes were 3* receivers, making them possession receivers based on what you just stated. So which is it, are both of those WR possession receivers or are not all 3* WR possession receivers?
Also, Martin is 2.5" shorter than Smith, but has a 2.5" higher vert. He also ran his 40 (4.57 sec) .2 faster than Smith. He put up the 12th best SPARQ score out of 100+ of the best players in high school football at The Opening this weekend. TOS ranked him as a top 10 performer on offense in 7 on 7's yesterday (with 4* and 5* corners guarding him), outperforming several 5* receivers. Maybe it's just me, but usually "possession receivers" are guys who are limited athletically in my mind.