Because it is auspicious to say "Amitabha". When all Buddhists meet, they will cross their hands and say "Amitabha" to each other as a greeting of mutual blessing. Amitabha, an ancient Indian Sanskrit, means "Infinite Light Buddha" and "Infinite Life Buddha" in Chinese, which means "Great Wisdom Buddha".
So, in fact, you should thank that old woman for helping you read the auspicious words of "Amitabha" for no reason. So you have forged a "good relationship" with the immortal Buddha. Congratulations!
Learn from Buddhism and support your above answers for your reference. Gratitude. Amitabha!