Re: This seems out of proportion to the offense
The issue with that approach is that it very expensive, both in the short term (housing/feeding the convicted and their family, who will likely end up on more benefits)), but also in the long term (children from said environment are not renowned for staying out of trouble for the rest of their live).
Community service however is much less costly, and still deprives the convicted of significant time - that no doubt they’d want to spend with family.
I’m not saying two weekends litter picking, but think what this country could do with hundreds of people doing community work every weekend for years...
“Why was dad never around on Saturdays” is possibly a more powerful question given the prevalence of single parent families.