There are some where the value you get from them is so small though that other operators would be more useful. Attacking dining room on chalet for instance. Yes, they could open the wall from trophy to kitchen or the hatch above kitchen, but it's really not necessary. Honestly a single smoke grenade can get you from trophy into kitchen relatively safely. You'd be better off with someone who has more pushing potential. Also a room like library on chalet there's really no need for thermite. Hibana could open the back wall from the opposite balcony, but then you're also opening kill holes for defenders outside the site when your team pushes in. So I'd say they aren't too useful for that OBJ either.