How can Biscuits made by Cracker be so damn hard??? Haki.
If he makes them hard using Haki then he could have just made sth else hard.. It'd be smarter to just use his devil fruit power which produces biscuits that are always readily available.
Why waste the ability to swim for biscuits? If those biscuits can tank a kong gun from 4th gear Luffy, losing the ability to swim holds no weight in comparison.
And did that scar on his face made him fear pain?? Maybe we'll find out next chapter, who knows..