Hey! Honestly, I don't think this would be a great idea. Credits are given to players only in minigames, and have absolutely no effect in sub-servers, like creative. While I can understand where you're coming from, I don't think it would work, as some players have hundreds of thousands, or even millions of credits piled up, after they've bought everything on the server, across all minigames. While there is a cap on how many plots one can have (11 with immortal rank), if anyone with any rank could buy up to 11 plots with their credits, the plot world would run out of space quickly, since a lot of players will have nearly 10 times as many plots as they did. They've already expanded the plot world, allowing space for more plots, however they'll have to keep expanding this even more, as more and more players will join the server and gain enough credits to buy a lot of plots. As more players have more plots, it uses more resources from the server, as the world file will get bigger every time they expand the plot world. Keep in mind that, ranks bought from the store pay for the technology keeping the server running, and not credits, which do not have any real-world monetary value. So, this will also be en economical loss for the server, if they implemented it, and could likely cause crashing of the server and/or players, too, degrading the quality of the server. Because credits are only obtained and spent in minigames, and not on sub-servers, and players getting a lot of extra plots could use more server resources, I'm going to say -1 on this. Most ranks aren't extremely expensive, and they're even cheaper if you wait for a sale.
Hey there! Creeper pretty much summed this up quite well, but the main point is that credits are for Minigames, and suggesting that they should be used to buy extra plots on creative is like suggesting you should be able to choose an ancient key reward with credits as well. Personally, I feel like it's just easier to buy a rank, especially during a sale. I can't specifically remember how much the sale was, but it was over 40% off when I first bought diamond rank, in 2018. I got it for about $20 cheaper than the normal price, which just seems easier. I think ranked perks should stay as special as they are, and finding ways to get around buying a rank for these perks just makes it less special to have. Thanks, Nikki