All machines such as kegs, furnaces, and preserve jars should allow you to take the finished product and insert new item(s) with 1 input press. This change would make emptying and refilling machines such as kegs so much nicer.
I honestly thought this would be added in 1.6 tbh, it could be incredibly useful on mobile and console especially where it’s hard or impossible to use multiple key presses to ensure you’re harvesting and filling at max speed.