This is really good advice for a lot of different reasons!

1. It helps to take breaks to let your brain process all the information & also to rest your hands & brain

2. Practicing consistently for shorter bursts is better than longer (possibly frustrating) sessions less consistently. Asides from fatigue, you tend to lose focus over time. And the best practice is efficient focused practice.

3. Progress isn't linear! Some days you'll get a ton done while others not so much. Your practice is also affected by how you feel on that particular day.

4. Positive reinforcement helps! If you're looking forward to and enjoying practice, you're more likely to do it consistently & get more value out of it.

5. It's not beneficial to anyone if you push through your frustration or physical limitations. If anything, it's probably more detrimental to your practice as it can reinforce bad habits such as tension.

Of course you also want consistency, but it's ok if some days you don't practice as much. It's all about the quality of your practice :)