I purchased this to hold business cards.  Technically, it works for that, but it is much tighter than I expected - I can't get many cards into it.  I expect that if you use it for a wallet you'll find that you can't get as much into it as you would like either.  Because it is so tight, it is also difficult to pull things out of it once they are inside (a big problem with business cards that will tend to bend or tear; maybe not as big of a problem with credit cards or cash).  The leather on it is very thick, so the wallet itself is likely thicker than the combined thickness of what you'll carry inside of it.