What do the "Coffee-Bot" coffee machines do?

In the description it says "Click to get a minor/medium/big speed boost for one job" and it costs 500/1000/1500 money respectively. I got the most expensive one and I can click it at home and it makes a sound, but I didn't see the effects obviously on the following job.

What does the coffee machine speed boost speed up? My movement? The movement of the queue?

Solution 1:

It offers a very minor boost to how fast you move between queues. It might shave a few seconds off, but ultimately, it's a really small benefit, that you have to remember to click for. If you've got an excess of money might always be worth it.

Source: This Steam Community thread