Agressive host checking

I had recently a problem because this option was not turnet on (the same described in the tuning tips):
the host recovered but the services were still in an Non OK state (=critical); meaning I was still notifying a host down where it was a service down error…

So, as I was looking for solutions, I came across this option; on which it is said at least 4 times that the nagios author do not recommend to turn on, without really giving any reasons.
My question is: WHY is it recommended to let it turned off ?
Does that mean that nagios delays all the other checks to do the host check, as it is done when the option is turned off ?
Or is it “just” a performance issue ?
And are there any other effects resulting from this option ?

Also, is there a way to “turn this option for only some selected checks” ? (I mean: I don’t really want to do agressive host checks on my ~1400 hosts; only 200 of them would really need this option)

Anyway, thanks in advance for your help.
Also, don’t hesitate to detail a bit more than I asked :slight_smile: