whether or not something is worthwhile is a subjective opinion
...I was about to stop there, thinking that what Be-Jammin Franklin wrote was kinda pointless since worthwhileness is subject, but actually I think one of the key insights people should take away from MBTi is related to that: everyone naturally has different interests and opinions of what is a worthwhile use of their time.
Inuitives are focused more understanding how things work. Sensation people on doing things. Each 16 have certain skills and tend to seek activities that those skills help them to excel at, and everyone has unique tastes, experiences, and beliefs that shape their interests and what they consider worthwhile.
We should realize and accept that, rather than judge others and be pretentious that others don't share our interests. When it comes to how our interests and outlooks of others differ from others we should strive to better have better understanding and patience with people with different interests and outlooks and encourage them to pursue their interests and apply their unique skills and ways of doing things.
overall life and developing as an individual is all about trying to figure out what you personally find worthwhile and striving to do that.
To say you need to do things that are worthwhile is kinda cliche and obvious. The difficult part is figuring out what things you personally actually find satisfactorily worthwhile...and then once you figure that it can also be very difficult actually getting to a place where you spend your life pursing those things. Since the things that satisfy are not always obvious and often lie far from the life we're given, living a worthwhile, fulfilling life can be a struggle :/
also that quote kinda makes franklin sound like a dick. as if he arrogantly thought the interests and pursuits of others weren't worthwhile and he was bragging about inventing things and such...i remember learning that he was a coke fiend who disowned his son or some such, so maybe he was a huge prick, I dunno, people are complicated, or i'm guessing franklin was complicated and he was dead before any recordings were made to better judge and what does it matter if he was prick anyway