If all you need is to be intelligible to the (same, small group of) people you see every day, then a local, short-lived argot will suffice.
If you're talking to people in the next village, town, state, country, continent, and/or planet over, regularly, you're going to need a more stable form of spoken comms, and coordinated evolution is more challenging.
Much as small island populations tend to evolve and diverge more rapidly than large continental ones.
If all you need is to be intelligible to the (same, small group of) people you see every day, then a local, short-lived argot will suffice.
If you're talking to people in the next village, town, state, country, continent, and/or planet over, regularly, you're going to need a more stable form of spoken comms, and coordinated evolution is more challenging.
Much as small island populations tend to evolve and diverge more rapidly than large continental ones.