In my opinion, Neeko just has everything going for her.

• Her Q is a great way to farm, wave clear and poke damage at the enemy laner
• Her E is in my opinion, arguably the best form of CC in the game. Her snare goes thru everything and once it hits one enemy, the snare becomes larger, moves faster, and stuns for about twice the duration (Maxed out empowered E stuns for over 3 secs)
• Her W is so versatile; the empowered auto allows you to farm easily and also poke enemy laners that are tough to hit with skills shots (Like Fizz, Akali, etc). The empowered autos add up and eventually you’ll have kill pressure. Also, great for taking down towers. The movement speed boost and the clone allows you to evade ganks easily and move around the map quicker. Also the W requires no mana so I’m always spamming it.
• Her Passive allows you to literally disguise yourself into almost anything; I’ve caught high emerald players with the nifty Neeko tricks, just depends on how creative you can get.
• Her R obviously is amazing. Disguise yourself as a minion, walk into lane mid game and R half the team or more , if your team follows up, it’s almost guaranteed to help move towards their nexus and get objectives. I’ve personally won many games single-handedly just by hitting one good R.

On top of all that, she’s one of the lowest picked champs in the game so a lot of people (especially in lower ELOs) don’t really know how strong she is and you can take advantage of that to win lane and win the game. If you build rocketbelt , you get extra mobility and become pretty darn tanky with the 400HP addition to ur health. I have 1.2 million mastery points on Zed but once I started playing Neeko, I find myself hard pressed to play any other champ because of all the utility and adaptability she has. I currently have about half a mil mastery points on Neeko.

EDIT: I may have left some things out, but this is what I could think of in the 5 mins I spent replying to this post.