A button is an important element in a user interface. First intended to submit forms, buttons were quickly used to emphasize the importance of a certain link.
Split tests have shown that additions like «now» can increase conversion rates. After that, some have started to include more and more convincing text into buttons, until they got so long that they were no longer perceived as buttons.
Take this action
Keep button text short and actionable. If needed, add additional elements besides the button to convince the user to click the button.