Short version: They shouldn't.

Or at least, not ones that have the collectible rewards locked behind them. As it stands Frontline has been boiled down to as much of a 'player friendly' 3-way experience as possible. Meaning that 66.6% of your time will feel entirely wasted when it comes to progressing towards those achievements.

It's probably just wishful thinking blowing air into the wind, but an easy change would be to alter win to participation. Increase the required amount and overall it would be a net improvement to the experience, knowing that at least you're making progress.

It certainly isn't prestigious in any way to have win-based achievements, because it just boils down to getting lucky and being on the team that is most competent in the match. The difference between winning 100 games and participating in 300 is quite literally nothing with the current design, yet one would be far less destructive to motivation when you go on those streaks of nothing but 3rd place.

Frontline is so flawed that putting emphasis on winning is just rubbing salt into the wound.