Does really someone eat gluten-free foods if they don't actually need them? Sure, if you have a disease and you cannot eat gluten obviously you will eat them, but otherwise?
I'll defer to old engineer's answer, and then I'll explain why this isn't
quite off topic, but I'll also mention that people who abstain from gluten "just because" are in the vast minority. Most people have either celiac's disease, which means eating gluten means a trip to the emergency room, or they have either a wheat allergy or gluten sensitivity (which means gluten will cause them to break out with acne, have indigestion, fatigue, etc.) Very hard to realize this is the cause as it's such a ubiquitous item in the Western diet. However, the mainstream media tends to portray it as (1) a small minority of celiacs buying the products out of necessity, and (2) a large majority of fadster hipsters buying it for no reason.
This may seem off-topic, but we are outlining a case in which a perceived "niche" value of an item causes an excess margin which many people are willing to pay. And this is most likely what DigiDeals has done with their 5% bitcoin fee. They know a lot of bitcoiners are staunch ideologues who support the anti-fiat cause and will buy something with bitcoins over fiat, even if it means a 5% fee.
Someone asked if it's worth "5% of your money." It's not 5% of your money, it's 5% of the purchase price. Big difference. If I bought a physical good in a store in my area, I'd pay 6% sales tax. And that'd be fiat. Most of the gas stations around here charge 10c more/gallon when paying with credit card. So it's not like we're not used to paying ridiculous percents of our purchase price for stupid reasons. With Bitcoin, I'd already have made more than 5% in appreciation between my DCA "date" and the time of purchase. Now, the question is, do I want to pay a 5% "niche" margin because I'm using something that is "hip" but actually costs the company less to process than other methods? No, I don't. So chances are I would choose a competitor. Or, if the 5% would be more than $5, I might use Bitspend which would serve a similar purpose. It's not like DigiDeals isn't converting the BTC right back to USD as well.
The 5% fee is a non-issue. If people are paying the 5% fee, that's their choice. If people aren't paying the 5% fee, DigiDeals will either lower the fee or stop accepting bitcoins. They accepted bitcoins for a reason; they're done their homework, so chances are if their bitcoin sales increase doesn't mirror that of similar companies who have begun accepting bitcoins, they will blame the fee at one of their boring board meetings and decide to lower it.