In 99% of slides, it is better to round financial data. $1.9m is easier to read than $1,898,456.34. Also the rounded number is more in line with a financial model that relies on rough assumptions. If you project your company sales in 10 year down to the dollar, you lose some credibility with your audience.
In some situations, the opposite approach can work. Look at this poster below of an Israeli anti-vax group who makes the argument that the money that is spent on encouraging hesitating Israelis to get a vaccine, could have been used better in a different way. (I leave pro and anti-vax debates out this blog, although you might guess in which camp I sit).
Here the big number actually works. Anyone looking at this big amount of money instantly starts comparing it to other lump sums you know: how much do you make as an individual in a year, how much does a car cost, how much does an apartment cost. Also, the precision and suggested accuracy of the number adds to the drama. This is a similar effect that National Debt Clocks try to convey.
The correct way to look at these numbers is to relate them somehow: $ per citizen, % of total corona-related cost, compared to other government advertising campaigns, etc. etc. After that, you might still conclude that it is high, but you used the correct metric.