You need to learn/determine one big thing: what's my game plan?
First you need to determine who's the beatdown and who's control. In most cases, you're the beatdown: you are the faster deck and need to close the game quickly. Unless against other hyper aggro decks like Aggro Shaman you might be the control. And I'd say usually only if he gets a fast start with Troggs, as usually he is mostly burn and you are mostly creatures.
Than, you need to know how you win. Most of the time, you win by attacking face each turn, only killing minions when they are a threat that can reduce more of the damage output in upcoming turn than you lose by killing them. You usually clear them with weapons as that loses you momentum/overall damage. In rare cases, against a another fast deck, it will be a race to deal 30 damage so you might need to recognize when you are losing the race and start contending the board.
Now, Healbot doesn't help you with your main plan at all. When you cast it, you used 5 of your mana for subpar body and you get yourself.. what? Some health back? Does it really matter? You are pressuring your opponent, your shouldn't be under the pressure yourself, you are not really advancing your game plan. What you are doing is applying less pressure, and giving them additional turn, which might be enough to stabilize. If you played a charger for those 5 mana instead, you'd be going in the right direction.
It does help you with the race, true. But a charger would help with the race as well. There are some nieche matchups where it actually does matter (Druid perhaps) but overall it does not give you what your deck needs, either.