Hanifin was never really considered an offensive defenseman. Always seen as more of a mobile 2 way defender.
Except for the fact that Hanifin scored at a higher rate in a lower scoring era through his first 4 years in the league, and had already broken the 30 point plateau twice as a 20 and 21 year old, something Nemec has yet to do.
Nemec may ultimately end up the more productive player (we haven't seen that yet), but his offense comes at the expense of his defensive responsibilities, where he flies the zone early and is constantly making high risk pinches at the offensive blue line.
I know you're a Slovak homer, but take off the glasses. Hanifin was the significantly more steady, reliable defender compared to Nemec. It's not even remotely close. Nemec hardly even touches the puck to help his team break the puck out. He's near the bottom of the league in terms of retrievals and zone exits. And he's constantly putting his D partner in terrible situations, forced to defend multiple odd man rushes per game.
They are separated by at least 2 tiers in terms of talent. Mostly because Hanifin's skating is an order of magnitude better than Nemec's. One guy is the clear cut #1 5v5 defenseman on one of the best teams in hockey, while the other projects to be a top 4 D if things work out, a level he's still very far from if we're being honest.