As long as I've been playing Widowmaker, which isn't very long, I've been ... pretty much uniquely aggro with my mines. They're part of my offensive weapon toolkit. Enemy team gets one as soon as they leave spawn, they get another as soon as they touch the payload or reach the choke, they get as many more as I can stuff in their faces, etc. I got the award spray for mine use the first day I played Widow seriously in quickplay, and I've seen very few Widowmakers come as close to the kind of harassment I dish out with the mines.
...it turns on wallhacks for affected players.
I'm seeing at least parts of teams all the goddamn time now. It is nuts. Suddenly, no one escapes from my sight is serious fucking business, and I am going to goddamn town with it.
Honestly, I read that note in the update and my eyes got big 'cause I realised right away - this is quietly massive. Once other Widowmakers start figuring out how this works with the mines, every one of 'em is going to start dropping mines expressly for this purpose. Good teams already aim for 'em, but there's only so much they can do.
Also, the Junkrat buff is a huge deal. Look for divebombing Junkrats from above, 'cause they're gonna be raining down on you. One of my housemates is a Junkrat main and he was already a pretty srs bsns divecomp player? ("You play Junkrat like Genji, what the hell?") But this double-mines thing - yeah. Watch out.