Mortarions Hammer Thoughts

Im a newer player and did my first RTT last weekend. I had a blast and im planning to do two in november. Ive been sticking with the hammer detachment as i learn because its pretty straightforward but post nerfs there's been a significant pivot away from it towards VV. Over the past couple weeks the winrates have dropped as well on stat check.

Could some more experienced players here than me help me understand what strategically is driving this? Like is it just the points nerfs has brought down the damage output enough to limit viability? Has the meta shift just given it a higher likelihood to run into bad matchups? Whats the problem its consistently running into?

Thanks in advance for helping me learn.