Oh, I'm all about making objects more useful and tweaking SMW gameplay to make it more rewarding to the player. My hack
does two things with coins (which are spinning watches). First, being watches, collecting them increases your timer. Rarely, you have levels where the timer begins at 0 and you don't want to collect any coins, as they become a hazard. Secondly, it uses a modified version of the 100 Coin Roulette patch, giving you a random powerup or an extra health point (it has a health system utilizing 1UPs, also making those a lot more useful to the player). There are also hazards which rob watches from you (clocks spinning quickly backwards) or speed up the timer when you are in contact (clocks spinning quickly forwards). In some levels, health and powerups are rare, and collecting watches becomes your primary source of these. Dragon coins appear as food items, which have the same functions as in vanilla SMW, while also adding 20 seconds and 20 watches to your totals.
In other words, coins are integral to the gameplay, rather than a pointless collectible gifting you a pointless reward.
SMWC members who have helped make Ganymede the hack I want it to be