Question about Humble Bundle Purchase

Its not linked to your account , humble doesnt do that for really long time now.
You need to manually activate the key to your steam account After revealing it .

So you can gift it here .

You can giveaway the key. What they mean is you won't be able to generate a gift link anymore once you reveal the key.

In general, gift link for giveaways is better, so do that when you can. Even if you change your mind, the default setting is to redeem the gift link for your own account to get the key later.