I'm the case of identity theft/card #theft, credit cards provide limited liability, while debit cards do not, at least in the USA. How do you plan on protecting your customers if they want to use the card for on-line purchases and are therefore exposed to this risk? Or can you even us debit cards for online purchases?
You can use Sequin anywhere Visa is accepted (online, offline, etc). A cool feature is, you can actually set your daily limit on the card which protects against fraud - over traditional debit and even credit.