This could be very misleading

> net power grid imports are less than 5% (17% imports vs. 12.5% exports in 24H1)

depending on when those happen. If they import French electricity whenever the wind is taking a break from blowing, that prevents craptons of pollution (including, but far from exclusively, CO2) from the massive German coal plant I live near to. If it's more random, say if it's just helping with some peaks when everyone's making bratwurst and coal currently doesn't cut it, then it's not reducing them from running

There are also times where we hear electricity prices are negative or near zero for a time, afaik usually caused by too much wind-based production. Exporting that may balance the thing out so that the net value is near zero

I'm sure it'll be some mix of those and other scenarios, but I'm not sure that looking at the net result says very much about whether nuclear electricity exports helped reduce emissions in surrounding countries like Germany. I'm more inclined to say the claim of the person you're responding to is likely correct (though I'd say "helpful to be" part of the mix, rather than "needs to be")