What is the purpose of HAL_ADC_PollForConversion in STM32 HAL ADC code?

while (1)
{
    HAL_ADC_Start(&hadc1);
    HAL_ADC_PollForConversion(&hadc1, HAL_MAX_DELAY);
    
    uint32_t value = HAL_ADC_GetValue(&hadc1);
    float voltage = 3.3f * value / 4096.0f;
    
    printf("ADC = %lu (%.3f V)\n", value, voltage); // send the value via UART
    HAL_Delay(250);
}

while (1)
{
    HAL_ADC_Start(&hadc1);
    //HAL_ADC_PollForConversion(&hadc1, HAL_MAX_DELAY);
    
    uint32_t value = HAL_ADC_GetValue(&hadc1);
    float voltage = 3.3f * value / 4096.0f;
    
    printf("ADC = %lu (%.3f V)\n", value, voltage); // send the value via UART
    HAL_Delay(250);
}