Because similar to a commander in EDH, you can always count on having it available without having to draw it, which is very powerful
Students can pin these pins to backpacks, pencil cases, or hats, extending their love of Pokmon from the screen into their daily lives
Aggressive decks that play pump spells tend to operate on few lands, so it can be difficult to cast a threat and leave up much interaction on the same turn
Its limited to once per turn, so you can point your removal spell at your opponents creatures to make it work on their turns
In blue you have better options

Sort Card Type Tynamo #59Common $0.16 Tynamo #31Common $0.26 Tynamo #62Common $0.15 Tynamo #44Common $0.47 Tynamo #57Common $0.08 Tynamo #95Common $0.24 Tynamo #59Common $0.12 Tynamo #67Common $0.12 Tynamo #30Common $0.21 Tynamo #47 $0.16 Tynamo #33Common $0.07 Tynamo #39Common $0.13 Tynamo #32Common $0.15 Tynamo #38Common $0.18 Tynamo #15Common $7.58 Tynamo #36Common $0.25 Tynamo - 024/094 #24Common $0.25 Tynamo - 025/094 #25Common $0.33 Tynamo - 033/086 #33Common $0.08 Tynamo - 033/086 (Master Ball Pattern) #33Common $4.66 Tynamo - 033/086 (Poke Ball Pattern) #33Common $0.19 Tynamo - 10/15 #10Promo $0.28 Tynamo - 113/086 #113Illustration Rare $19.43 Tynamo - 117/086 #117Art Rare $13.70 Tynamo - 2012 (Chase Moloney) #45Common $1.55 Tynamo - 2013 (Clement Lamberton) #38Common $0.94 Tynamo (38) #38Common $0.28 Tynamo (39) #39Common $0.32 Tynamo (44) #44Common $0.31 Tynamo (45) #45Common $0.37 Tynamo (63) #63Common $0.18 Tynamo (64) #64Common $0.16 Tynamo (Energy Symbol Pattern) #59Common $0.18 Tynamo (Master Ball Pattern) #30Common $2.94 Tynamo (Poke Ball Pattern) #30Common $0.29 Tynamo (Quick Ball) #59Common $0.25 Tynamo - 113/086 #113Illustration Rare $19.43 Tynamo - 117/086 #117Art Rare $13.70 Tynamo #15Common $7.58 Tynamo - 033/086 (Master Ball Pattern) #33Common $4.66 Tynamo (Master Ball Pattern) #30Common $2.94 Tynamo - 2012 (Chase Moloney) #45Common $1.55 Tynamo - 2013 (Clement Lamberton) #38Common $0.94 Tynamo #44Common $0.47
