There's additional context here. Widows were not allowed to remarry. They were made to spend the rest of their life in mourning, basically - shaving her head (or at least wearing it unbraided, "the knotted hair of a widow becomes bondage for her husband"), wearing only coarse white sarees with no blouse underneath, not wearing makeup or adornments, only eating one simple meal a day and abstaining from any rich or intoxicating food, not attending festivals or celebrations like weddings or even really leaving the house at all, not talking to men, not making eye contact with men, avoiding making friends with anyone, not looking at herself in the mirror, not being alone with any men including male relatives etc. etc. This was predominately the Brahmin caste and applied to any widow, including little girls who'd been subjected to an arranged married that had never been consummated. Her entire life purpose from that point onwards was basically to be an ascetic nun to mourn her husband and pray, and otherwise raise the children or do housework (but while sticking to all the requirements not to interact with men) because she was being punished for failing to retain her husband's soul and "had no reason to live".
So from the perspective of the husband's family, they were a massive burden as they couldn't really contribute to the house properly and were no doubt depressing to be around because they weren't allowed any sort of pleasure whatsoever. There was also a liability that if a widow decided not to live the world's most depressing life and carried on leaving the house or wearing her own clothes then she would bring great shame upon the husband's family, and anyway things like child rearing could be taken over by any number of the other wives and daughters of the household - which is why Sati was so encouraged. The East India Company changed the law to allow widows to remarry... but you can't legislate away religion. To this day in rural areas, Hindu widows are often shunned by their community and thrown out by their in-laws and rejected by their families, which is why
the city of Vrindivan is home to over 20,000 widows living in widow ashrams.