I think most generally add their hops to the boiling wort - if doing Extract, Partial-mash, BIAB or All Grain methods. But if you are doing a simple K&K (using a Coopers can of hopped extract, which is added to the FV and then water added to 20L or 23L etc.) then steeping in some boiled water is fine.
The point is probably more about how long you steep for - the long the steep the more bitterness will be extracted from the hops (generally speaking - also depends on the variety of hop or hops). A short steep (i.e. 5mins total) will give you less bitterness and a bit more aroma. Though any late hop addition will have a certain amount lost due to the fermentation process and the expelling of the CO2 (eg. aroma will be expelled etc.).
So dry-hopping is generally considered the best method for adding aroma and flavour. Generally 3 to 5 days out from bottling/kegging is considered a good dry-hopping period.
I guess the other more recent style/method, New England IPA, sees you adding few hops in the boil. Most are added at periods like: 2 days after fermentation has commenced, then multiple dry-hops at 7 days from bottling/3 days from bottling etc. This appears to give the beer a very fruity flavour and aroma but also makes the beer very hazy from all the hop particle. The method does kill a lot of hops. So you'll need a fat wallet.
Some of my typical dry-hops for my IPAs and Pale Ales use 100grams to 200grams around 4 days out from bottling. The other side to this is that these styles are then best drunk fairly young (i.e. within 4 to 6 weeks after bottling), as the hop aroma/flavour does start to dissipate after that.
These are my learnings from brewing over the past 5+ years.
Cheers,
Pete