To be honest, no, they're not worth it with LT on 100% as you'll definitely be in ketosis if you stick to it. The only time they're useful is when you know you're out of ketosis and you're monitoring how long it takes to get back in. Bear in mind too that they should be used on your first wee of the day upon waking, after that it'll be too dilute and mostly test negative (falsely)
Hope that helps x