Yes sir, but the newer R4 cards have built-in DLDI patching, so this isn't an issue anymore.
The only real worries using a new R4 card (particularly one that runs on all DS's) is not to update the firmware on their DS units, to ensure card usage, and that they don't/can't play GBA game roms.
(Their are a couple of other flashcard types that do, but i forget the names...)
I have 3 DS's (albeit not the original DS or DSi-XL), and it is really nice to share the usage of the R4 card between them all, at will.
The DS Lite is my beater, the one i have for heavy, random usage on the go, a brand new DSi i use for the really good, deep, immersive and involving games, when relaxing at home and the 3DS for all of that and to enjoy the new games that have recently been released.
Just some versatility is what i like about this setup, and if one should ever be destroyed or become prone ro some kind of failure that i can't fix, then the gaming enjoyment can continue on another of my units...