Will the US business suffer from the increased labor costs?
Yes , because many businesses are suffered also in pandemic then if Biden did not pair for this happen many businesses are going to close and shutdown.
Will Biden and the democrats keep their promise?
I dont know if Biden and her fellow partners do the promise in US but if we do, there are many bad effects to the economy of the US.
Stupid question:Will the American working class buy more Bitcoin,if they have bigger salaries?

Some economists say that the current federal minimum wage is way lower than the labor productivity,so increasing the minimum wage will lower the profits of the business,while boosting the consumption of the working class.
About that we dont know because if American Worker know about Bitcoin why not , if im a worker then my salary increased because of Biden promises i then i buy more Bitcoin to hold.
Yes , the increasing of wage can affect mostly in businesses , this time we need be fair to businesses and workers. Biden need to study more if what is the good in their county.