In some very specific circumstances -- like you’re training for a physique competition -- spending lots of time on isolation exercises for smaller muscle groups makes sense. For the vast majority of people? They’re a time suck.
Most people don’t need to do more than eight to 10 exercises in a single strength-training session, and most of those moves should be compound exercises that target multiple muscle groups at once. Exercises like squats, lunges, push-ups, and pull-ups target larger and smaller muscle groups at the same time, making excessive isolation moves largely unnecessary.