Of what importance are Mrs. Hale's descriptions of Minnie as a young woman and the Wright's marriage?
The men are there to look for evidence. They essentially are looking for some motive and some way to connect Minnie Wright to the crime. The women end up finding the essential evidence and in the process, they talk about who Minnie was and who she became during her marriage to John Wright. Mrs. Hale points out that the marriage was not a pleasant one. She also points out that Minnie Wright was a different person before she married John. These descriptions are significant because they show the toll the marriage took on Minnie's personality. Minnie was once happy in life but her marriage to John took that away.
Note that Mrs. Hale refers to her as Minnie Foster (her maiden name). It's as if Mrs. Hale prefers to remember Minnie in this way, different from the less vibrant woman she became: Mrs. Wright.
When asked why she hadn't visited Mrs. Wright much in recent years, Mrs. Hale replies that she didn't feel the house was that welcoming. She says, ""But I don't think a place would be any the cheerfuller for John Wright's bein' in it."
Mrs. Hale says that Minnie "used to wear pretty clothes and be lively--when she was Minnie Foster, one of the town girls, singing in the choir. But that--oh, that was twenty years ago." Mrs. Hale clearly shows that Minnie was more vibrant and much happier before she married the ironically named Mr. "Wright."
One of the most striking images is the dead canary. Mrs. Hale notes that Minnie used to enjoy singing, but John put a stop to that. "No, Wright wouldn't like the bird," she said after that--"a thing that sang. She used to sing. He killed that too." With this comparison, Mrs. Hale implies that Minnie had once been free like a bird, but had become caged in a cold, unhappy marriage. With these descriptions, Mrs. Hale suggests (but perhaps does not completely condone) reasons why Minnie would have committed the crime. The suggestion is that it was a retaliation for years of marital repression, culminating in the last straw: John killing the canary.