Interestingly enough, ecommerce conversion rates for tablets are comparable to those of computers, with a rate of 3.78%. While these are ecommerce site stats from the third quarter of 2018 specifically, the numbers have remained in similar relation to one another for the past two years. This shows that smartphones are primarily used for browsing, while desktops and tablets are where the actual transactions take place.

Source:
https://www.smartinsights.com/ecommerce/ecommerce-analytics/ecommerce-conversion-rates/