Before we launched the first-generation Tenuis in Japan, while I was living abroad, I had a wallet made entirely of canvas—both inside and out. That was about 13 or 14 years ago, and I believe it was right around the dawn of the smartphone era.
Since I was living abroad at the time, I designed that slim wallet to accommodate a passport. At the same time, because smartphones back then were smaller and thinner than they are today (I believe it was around the time of the iPhone 4), some of the customers who purchased it reportedly used it by slipping their smartphone inside the wallet.

This wasn’t exactly the intended use for us as the makers. However, from the users’ perspective, the size fit perfectly, so it naturally became a common practice. Nowadays, smartphones have gotten larger, so to be honest, I don’t think many people would consider using one with a minimalist wallet due to size constraints.
Speaking from designer Sola’s perspective, I feel—intuitively—that it’s better to keep your smartphone and wallet separate. The reason is that if you were to drop them, it would be a real problem if both were lost at the same time. Also, no matter how thin and compact the wallet is, adding the thickness of a smartphone will inevitably make it bulky.Furthermore, there’s the issue that it adds an extra step—you have to take it out of your wallet—if you suddenly want to use just your smartphone or just your wallet on its own.
That said, it’s true that seeing a smartphone fit neatly into a wallet gives a unique sense of satisfaction—as if everything had come together perfectly from a design perspective. I don’t know if there will be demand again in the future for wallets designed to be used with smartphones, but if such a time or opportunity arises, I might try designing one again.
Related Article: When Your Smartphone Doesn’t Work! In Times Like That, “Cash in Your Wallet” Is Your Last Resort



