You can give jobs to a few more people, you can serve a few more customers, you can experiment with bigger ideas, you can have a bigger impact, and you can sell something bigger when it comes time to sell the whole thing.

But as you seem to already know, there's no reason that those need to be your priorities and pursuing them comes with added cost and risk. If you're confident that you can satisfy your personal goals without taking investment, there's no reason that you should.