It is more of a mistake now than in the past. In the 1930s, yeah sending checks to everyone as a form of stimulus would have been highly complex and difficult. Banks were the only society wide economic linkages at the time. That is less true today. Today you can sends cash to a large portion of people with existing infrastructure and clearly you could get near 100% with a dedicated platform/process to do so.

The argument for giving money directly to businesses is that it makes the recovery easier. Many argue that we needed to give more money directly to businesses, that it was wrong to let unemployment get so high when we could just pay businesses to keep people on.

Giving money to businesses to keep people employed is a non-starter in the US as there is no political will to ensure those businesses don't just furlough employees anyway and pocket the bonus - will for both writing effective regulations and post-hoc enforcement against businesses that skirt them.

It also directly creates zombie companies if applied to industries that can't possibly bounce back, like travel etc.

IMO the appropriate business-saving economic response would have been to statutorily suspend all rent/mortgage/loan payments denominated in USD. That's the bulk of most small businesses' fixed burn rate. Needing to service the debt black hole is our primary source of inflexibility.

Of course given that we're still "debating" whether the pandemic is even real or not, figuring out what is appropriate is purely academic. Enjoy your token $1200 while the looters loot billions.

Businesses have no incentive to keep employees on. If you want businesses to keep employees on then you offer to do exactly what the UK did https://www.bbc.com/news/business-51982005

This is not at all what the USA is doing. The USA is making a terrible, terrible mistake. Trickle down economics once again, and trickle down doesn't work. At least not for the bottom 9/10 of society.