I was a bit like that myself. I only bought Chop Shop because I wanted all three Insecticons (or as close to it as possible), but couldn't find the Thrilling 30 one for a good price.
I don't mind having Chop Shop as a fourth Insecticon after the classic three. I like having more Decepticons with Beast/Insect modes because it gives them more diversity. Personally, I'd prefer to have a second stag beetle Insecticon than ANOTHER Autobot car mould I already have (EDIT: unless the other Autobot car repaint was of a cool character).