If you really think that pink wards do not do much against stealth units, then you're completely WRONG buddy. They have quite a lot to contribute for you in specific well placed locations. Specifically for Evelynn since she has true stealth and doesn't have to activate an ability for stealth. Placing them in strategic positions always work simply the same as normal wards. In fact best time to still get some kind of vision on even Evelynn when in jungle is ward closer to her camps because you'll see her dueling the camps and you'll know where she is and which direction she begins to head and when to expect her.
Wards do A LOT buddy. Positioning your wards properly will keep you safe.
Also if you're not near turret and Shaco, Twitch, Akali, Rengar use their ability to stealth just drop a pink ward immedietly, if your near a bush when they do that, put it there you'll gain vision of them and any wards in that bush as well. You will immedietly see them, so always carry pink wards on you when your enemy team has 1 or more stealth based champions. Too many times I see people failing to have a pink ward against Akali's and don't use them on her shroud.