I have always used the accrual system for my schedule C because it allows my business to claim the expenses and the income earned in the same year, even if I don't receive payment until the following year. If subsequently I never get paid, I can write it off against income in some future year when it is obvious I will never be paid. (Companies do go bankrupt leaving shoppers holding the bag.)
For me, accrual allows me to know exactly what the profitability of my business will be before the end of the year so that I can make purchases to reduce profitability or hustle end of year jobs to increase it. And by the way, your first year of doing business you need to decide whether you are a 'cash' taxpayer or an 'accrual' taxpayer where it comes to THIS business and subsequent years you need to continue with the type you selected.