Comment by aguacaterojo

I understand what you are saying and don't fully disagree. You can allocate time & energy into immediate real world solutions while reaping the personal growth. There is certainly a balance.

The counter-point is that in the case of a web browser you are studying deeply one of the most impactful technologies to exist, and you will learn 80% of the most important lessons with a minimal working build, maybe 0.1% of the real thing. You may learn and execute much faster too because there is a clear blueprint, and you are likely riding a wave of passion that will carry your mind to places you won't have expected.

The perspective gained puts you in a much better place to identify & execute successfully more impactful work. The work may be the seed of something more important, but unseen or unknown yet.