The small single target heals from each healer pair up really well. In dungeons where you are responsible for all the healing being done it can be easy to start to transfer that full responsibility to an 8 man group and immediately look to use Lustrate or Cure II/Benefic II whenever you see heavy damage but I found that in most content, especially anything before level 60, that you can use Physick for heavy damage and it will add up to the required hp needed when your cohealer adds their cure/benefic. This can be important when working in a group that is stressing your mp and aether stacks with loads of mistakes and avoidable deaths. Sometimes Physick really is your best option but it is a very situational skill that sees less light as your level goes up. That's why a lot of people have wanted it to proc something beneficial like Whm and Ast but it seems like that will never happen. I personally wanted to see Physick become an ability temporarily every time your fairy does a crit.