I wanted to make him different for the sake of making him different basically. If i want to port an official plant and put it somewhere other than earth or store, i change its appearance or function slightly unless it's already sci-fi-themed. I thought a plant named "scrapdragon" would be funny and original considering that most snapdragons are just elemental variants. Removing the fire type from his damage was interesting enough.
And to answer the second half of your question: it basically sounds like "Did you make Mario's fireballs bounce because you didn't know how to make them go straight?"