As far as government spending goes (and it goes way, way too far) the UCCB isn't that horrible. It's not good, of course. The bromide 'the ends doesn't justify the means' is nonsensical in it's literal interpretation, however the essence of the thought, that you cannot do good by doing evil, is true. Good things are done with the money the government obtains through taxation (horrible evils are also manifested with this revenue) but they are overshadowed by the manifest injustice of threatening someone with incarceration in order to get their money. So it's great that parents get a nice check, but what about the people who that money was extorted from? How can we simply ignore them from this analysis?
But as far as government spending goes, this isn't that bad. First of all, the money is for many people a functional tax rebate. These people pay taxes, quite a lot of taxes, and so a grant from the state for being a parent simply makes them slightly less of a net taxpayer. And for the lower income parents who did not pay any tax this year, then this is a not so horrible form of welfare for people who are presumably poor. Plus these people, though low income this year, may very well be net taxpayers throughout some larger time frame, and again it functions for them as a tax rebate.
Then again there is another class of individuals who benefit from this UCCB, namely net tax recipients. Bureaucrats, politicians, police as well as people who spend their life on welfare and anyone who all in all collects more in taxes than they pay. This benefit will function as an increase in their tax consumption. While it is unfortunate that these people are helped by the UCCB they will also be the benefactor of many anti-tax schemes, such as tax credits, so perhaps we must take the bad with the good.
And when it comes to government spending, the bad can be very bad. Not only is dropping bombs on people in Iraq and Syria extremely expensive it also makes them hate us which can have unintended consequences or as the CIA calls it, blowback. Ironically this politically benefits the hawkish national security elites who dropped the bombs in the first place as the public clamours for the safety of an ever expanding warfare / surveillance state. But even less malicious examples of government spending can be counter productive or deleterious to the economic health of our nation. When money is spent at home on the war on drugs, what is gained? Children from poor families who saw an economic opportunity languish in prisons, our right to protection from unreasonable search and seizure is compromised and billions are wasted with nothing good to show for it. When money is spent on welfare, this provides a disincentive to work and is thus a double injustice, against both the taxpayer forced to subsidize another's idleness, and against the recipient of the dole, who is prevented from being forced by necessity to find work. While those of us acquainted with the dis-utility of labour might scoff at the latter notion, employment is critical to a person's development and helpful in shaping one's worldview and philosophy of life. And as the cliche goes, idle hands are the devils plaything, especially for youth, who's understanding of the world is still being shaped and are prone to fall into crime, drug use or other foolish mistakes. And again, if the money is spent to enforce regulations on the economy, ostensibly in the name of justice, is usually to cause harm. So if the government spends money enforcing a $15 minimum wage, for example, then this causes worse unemployment among low skilled workers (teenagers, for example) and this is terrible for the economy and the affected workers.
So given all the alternatives then certainly it seems attractive to simply give the cash to parents, without wasting it on bureaucracy, or war or counter productive regulation but the best thing to do would have been to not take it from the people who earned it in the first place. The government should not be in the business of wealth redistribution, and it is long past time that Canadians stopped imagining that the state is Santa Claus, because whatever you are given will be taken from you ten fold unless you happen to be an elite member of the political class.