I use Bitcoin to buy all kinds of legal things online, a lot of places offer a 5% discount or similar for BTC.
I actually stopped using Kraken when the price of Bitcoin went up, they had a minimum transfer of like .005 BTC, which at the time I signed up was only a few dollars, but when it peaked it was up till like $50-$60. One time I forgot to cover the transaction fees, and was a few dollars short, and completely unable to send money from my Kraken account too the person I was buying stuff from. I had to cancel the order, wait 3 days for the bank new transfer to come through, and then an additional however many days to send it.
Their network fees are (or at least were when I was using them) super inflated too. Kraken charged me something like $5-6 to send $100 of BTC to another wallet (at "economic" speed, which can literally take days if the network is backed up), but sending it from my other wallet only costs a few cents, even with high priority, and sends in minutes.
I completely removed ALL of my money from their exchange when they blocked margin trading for "average" people though. I used to keep a few hundred dollars in my account and use it as leverage for shorting. NOT enough to make any real money, but it was a ton of fun. Then they decided that you have to be a millionaire, and prove it, to play.
I think sometimes exchanges forget that it's people like us who made the exchange possible in the first place.