Generally I find the 'eliminate decimals' thing to be more about improving the polish/aesthetics than about confusion issues. People can understand 0.4 influence a month, but integers and '2 in 5' sorts of notation feel more friendly or casual, more like human speech and less like reading a report. That particular aesthetic can feel more polished for a game than having things displayed out with decimals. Obviously its somewhat a matter of taste too.
There is one advantage to integers, but it requires a more aggressive approach. If you only have a handful of different integer or near-integer values that something can change by, then it turns those things into concrete symbols for the player. So e.g. if the only increase values are always 1, 1.5, or 2, then the player can think 'ah, that one's a '2'', and it establishes a natural hierarchy of things that are easily remembered. If on the other hand you have 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5,1.7,2.1 then the player can more easily forget which action gave which benefit when mentally comparing things. If you want to go this route though, you have to take measures to ensure that there's no more than about five different possible values that the player is ever shown for a given class of thing (three would be better).
