I totally agree. Some web sites and services insistently make you believe that creating your own decks is piece of cake. In reality, they avoid mentioning any and all pitfalls you are going to encounter along the way and just try to sell you stuff.
There are too many things to consider, and the most important one is printing. Assuming that you get your hands on some good card stock and manage to nail the not-so-easy problem of cutting your sheets into cards, printing is still going to be an inpassable roadblock. Unless you own a typography press, you choices are limited to laser and inkjet printing. Both flavors are unsuitable for printing playing cards for at least 2 reasons: a) the 4-color CMYK palette is very limited when it comes to reproducing colors accurately, and b) the image that is created by such methods is not intended to be in contact with your hands all the time. Laser printers “fuse” wax and powder to the paper surface, which results in a raised layer that is prone to peeling off easily. Try to bend a laser-printed page or use some low tack scotch tape to see what I mean. Inkjets just put droplets of ink on the paper surface, which remain extremely fragile: they do not penetrate glossy surfaces, and when in contact with oils or moisture from your hands, they will “bleed” profusely, making your cards look like garbage and, most likely, staining your fingers in the process.
Note that problem A above can be solved by using so-called giclée printers that utilize 8, 9 or even 11 different inks. But those printers are still inkjets, so you still have problem B.
So, unless you plan to make a souvenir deck for your grandma showing some pictures of her beloved cat, print your cards professionally. Cheers!