Living from Alms, a "beggars" live, does not only help to increase an understanding of goodness and gratitude, it also prevent to develop wrong concert, beliving being independend while still having desire.
It protects to become corrupt, doing the path or teach, for food, getting in trade.
It prevents from becoming lazy by feeling secure and be stilled in regard of wants. It prevents also to dwell in areas where Dhamma couldn't grow and to settle once somewhere seems to be food-security.
It is the foremost right livelihood, taking on giving, don't trade with common societies, not getting involved in ways to gain food, stay untouchable.
It's a distinction to common life, the ways of householder, neither to trade nor to store up (even a night) and cook food. A way of livelihood not open to critique, not harmful for anybody.
At least, it gives one planty of time, people usual busy 60+ % of time to care about food, store, defend... day by day.
Last but not least, this opens also ways to work, give into, the greatest field of merit. And it's out of compassion for others, that those freed from all desires, still going for alms, still receive food. For how could people ever give into relation, increase Nissaya, toward the Buddha, Dhamma, heir, the Sangha? Meet the forth Heavenly messanger.
Some thoughts in addition, might be inspirations, from a previous answer: [Q&A] Why are Monks not given to grow their own food? (Right livelihood)