Mo Yan had no prejudice against Phoenix Men and didn't think "Phoenix Men" were bad. On the contrary, most "Phoenix Men" were ambitious, knowing what they wanted and would go to great lengths to fight for it. Such people usually achieved a certain level of success.
However, in a poor family, where everyone had to tighten their belts just to barely provide for a scholar, even if they could not afford to continue supporting him, they would not let the most promising child become a live-in son-in-law, would they? After all, upon acquiring the title of Scholar, the Government would grant a certain amount of subsidy each year. If he really wanted to advance further, leveraging the status of a Scholar, he could easily find a job to earn Silver Tael and continue his studies. It was just a delay of a few years' time. Wasn't this much better than becoming a live-in son-in-law?