OMG nobody uses the tins?!?! I ONLY use the tins. In fact as soon as I use all the starbuzz tobacco in the tin I wash it out and store the next tobacco I buy in the tins such as tangiers. The tins may not be air tight but I'll tell you that I have tobacco over a year and a half old thats still perfectly juicy in that tin. So air tight or not its gonna last you a LONG time. Also if you don't clean the rim of the tin for a while and you use a oyser fork like me to pick out tobacco then you tend to scrap the fork against the rim to get the excess tobacco that you don't need off the fork and what happens is the rim gets gummed up and becomes soo airtight that I've actually had to get a knife and cut open the tin because it was so stuck together.
And as for rust, I've reused the same tins for over 3 years and have absolutely no rust.
Its up to you but for as much money as you paid for starbuzz I'd be damned if I wasn't gonna use that pretty colorful perfectly sized tin to store my tobacco.
Best of luck.