I think the concept is fitting toward the game, but it feels a bit dull, and like others have said I don't see a huge people using it because of that. It does manage to be silly and unique while still fitting the game though, which is something that many experienced creators manage to get wrong, so I think you did good in that regard.
And also don't let the negative comments get you down, I think you've got a lot of potential and could make some really nice cosmetics if you manage to find or come up with some better ideas for hats.

Consume Leaf.

trade up fodder, low tier unusual fodder, new traders first unusual. youre probably new to making hats considering your promo art isnt that great, keep practising blender for promo and creating hats, but you need better concepts

bad hat, nobody will use it if its not unusual, dont use blender for tf2 promo if you bad at it

random object on top of Sniper's head.

fitting of the game, put probably would never be used

I don't see anyone using this.

Dust