Nope, not significant at all, you can lease a reasonable, "uberable" car for way less than $200/month (which already includes depreciation).

If the car is used on Uber for (a very conservative estimate) of 20 hours per week, ~150 hours per month, that's about $1/hour in asset costs. Let's say maintenance and what not costs another 50% of that plus another 50% of whatever, we're still talking $2/hour in asset costs, which is far less than minimum wage.