I don't think there's a "wrong" tripod for fireworks, especially if you use the 2 second shutter delay (although I don't think I did). Let me explain:
For fireworks, the tripod doesn't need:
multiple leg angles
center column that can be made horizontal or used upside-down (camera under the tripod) or split into two pieces (useful if the legs can go straight out, and the center column can't go horizontal; you need a really short center column in that case.)
About the only thing it does need to be is a solid support. If it vibrates, then you will need the 2 second delay, that's a pain. Has to be set on each shot.
So, you could find a reasonably priced tripod with braced legs (therefore only one leg angle) and it will work fine for fireworks.
If you want a more flexible tripod, that does have multiple leg angles, and whose center column can go horizontal, then you're looking at a significantly more expensive tripod. I spent about $160 for Manfrotto 190XProB tripod legs and maybe another $60 for the head I chose, Manfrotto now has 055XProB (Pro = center column can go horizontal), Gitzo has several center column angles. It can be really useful, but not needed for fireworks.
Many companies, including Manfrotto, SLIK, Velbon etc offer less expensive tripods that are still very good, and would be just fine for fireworks.