This. WARs get the most out of their healing if they let themselves drop to like 20k HP before popping BW. Especially 86+ because you have Orogeny which is an oGCD aoe that you can use immediately after.
When I play WAR though most healers immediately start topping me off, so I just use it immediately whenever I've grabbed both packs. Although, as healer I've run into a handful of WARs that just don't use it? Like I've sat there waiting for this one WAR to pop BW and they never did for the entire dungeon. It doesn't matter too much because I usually play SGE or AST, so I have plenty of sources of oGCD heals so I can still DPS while healing, but as someone that's actually played the class it confuses you when you first run into it.