Gas Arrow vs Gas Grenade

So, I recognized that my build seems outdated, because I am playing Mercenary and here exists Huntress in PoE2 and Gas Arrow.

Let's leave this fact out that Huntress can simply have x2 damage.

I want to use Crossbow and Gas Grenade. But I have to check stats of Gas Arrow and it's just about 40% more increased damage (12 lvl gem - 93% vs 123% attack damage), have no cooldown, can be also buffed by quiver not just bow, and the same level bow have the same damage as my crossbow (+\-).
In description of Crossbows and Grenades said "slower but do increased damage than other". Meanwhile, Gas Grenade and AGas Arrow have identical mechanics.
Like, why? Maybe I don't know something about the difference of Crossbows and, you know, just Bows?
I am a man of heavy hard wood and steel, tight bowstring, not an elf.

Any advise how to realize Crossbow in this situation?