Why not? Yeah it's really, really not very good, but that's until you get your core items, you probably can't win lane unless you use the headbutt them under tower 😃. Anyway after your core items you will deal TONS OF DAMAGE, that's without a tri-force. But you do deal a lot of damage, to the point when if you dfg, q, w and ignite an enemy they will be destroyed. And plus you've got your ult to survive all bursts in mid lane making you the ultimate counter.

Just a warning, there may be more puns

You want damage, it's quite simple really. You can't do anything without damage
However cooldown reduction is very effective as Alistar has long cooldowns so when they are reduced by 35% it's happy days, you can run through the fields of justice like a free cow, squashing any bugs(teemo) messing with you

DAMAGE

POKE. It may sound very stupid but you can poke well, you can q then w your opponent for an instawin trade as they will probably not be in range of you to counter the trade. And in lane once you get your ult you cannot die when it is up, as alistar would say, you can't milk those. So as you can survive any burst from a midlaner this means that any trade with your ult can be won. You will also want to roam a lot as Alistar has lots of cc and damage so your ganks are great

You have to play with balls, you can only win if you are manly. But be warned you can only play with your balls when your ult is up, if it is not up you need to play like a normal assassin. So when a fight breaks out aim to assassinate any carries, ADC or midlaner, and as soon as you are in danger ult, with your ult up, cc the enemies and whatever you do, DO NOT MESS UP THE WQ COMBO, your team will attack you like vultures if you do this, well if the enemy didn't die from your damage

So unlike jungle tf this is a lot harder to pull off, however if you snowball in lane you can pulverise your enemies into the grave, literally.
Remember this champion is not to be played like a xerath, you are either all in, or useless
Anyway have fun with this build and I'll see you on my next one, keep an eye out on reddit and remember as always, feedback is appreciated 😃