I think mostly since they get introduced right at the start of the game it is a big investment for a reward that doesn't last too long making you not really want it, while cheap beer is okay if u look at bevarage 2 u unlock it at thinking 4 but the investment would basically always not be worth it since it only last 60 seconds even if u could live that long as getting 5 coins at that time would have a base cost of 50s and a 100 death chance