I’m a big fan of both methods, However I only like to use them during the first phase of training.
Most people need educating on portion sizes, calorie content of foods, macro/micro nutrient levels etc
And during the first phase of personal or group training for weight loss this can be very eye opening to the client, and very quickly re-educates them to the foods they need.
However after the first 2-3 months has passed, the daily logging of calories, counting, tracking can just become annoying as the client now knows what they are eating and how much of it they require. Once the client is confident, I get them to stop tracking as to avoid overloading them with tasks.
If we need to we can always re-introduce it.
MyFitnessPal, tends to be my go to app for tracking.