I have my BoA account linked to Coinbase and for the most part, transactions go through. When I started out, I only did small transactions that went through without a problem. I did have several (still small) bitcoin purchases that were reversed when it came time for the transaction to clear a week or so after initiation, with no explanation other than "suspicious transaction." I sent an email pointing out that the price of bitcoin had risen during that week and it sure looked suspicious to me that they would allow one of my former purchases when the price remained stable, but then cancel this one when the price had risen. I wasn't nasty in the email, and I don't think that's what they were actually doing (then again, who knows?). They pretty quickly reversed the reversal and allowed the transaction to go through. That happened maybe 3 or 4 times last summer but since then I've had no problem.

Keep in mind that anything more than $10k per day is the magic cutoff that means you might be a drug dealer. For coinbase, I generally stay below that limit.