well I'd disagree very very heavily but I guess you could just lowball it to 29, and I can't really stop you because it's subjective
there "usually being a gap" doesn't really mean more than me saying that a graph "usually starts at y=0", I don't really think that's gonna fly, since there's still no purpose of there being a gap, when situations where there is a gap are a case by case basis, in which there are purposes (usually dictated by the units, since most graphs have units, but not this one)
and it looking nice also doesn't really apply here. While it made some sense for the previous point in which the exponential growth should be noticeable (even though it would be definitely noticeable far before something like 29 times multiplier, and I'd say it's much closer to 5 than that) here there's no actual purpose, outside of the completely subjective idea of what a good looking graph would be
and the axis being there to make it look like a chart? not entirely sure what that point means, actually, so I won't really bring that up yet
recall my previous argument, here's a quick summary
the x and y axis are highlighted to differentiate them from every other line and square on the graph, but why? If you got rid of that, it wouldn't even "look better" since you could just make the x axis start right below it without leaving the gap, or make it start 500 squares lower and it would do the same. So uh, what exactly is the point of it? If it were quite literally any other non zero value then it would be quite pointless to have any lines as the axis. Doesn't make it look better, but if it were 0 then it actually means something as a multiplier.
what I'm saying is that when there's a deliberately added detail that serves no purpose other than having the graph being a multiplier, then that's evidence that it was meant to be used as a multiplier