Hi mischa -- welcome to the forum.
You indicated that you're new to Spyderco, but left room for yourself to own other knives. I think that is potentially a significant factor in whether you need to buy a drone or not.
The knives for which there are training models are all used/carried frequently in a self defense role. But, excepting the Gunting, there are many more of these knives that are carried strictly in a utility capacity. For one, I can't see buying a trainer if you don't plan to use the knife in a self defense role, unless you're only 6 or 7 years old.
The training that is anticipated for the drones is self defense training. They aren't for practicing to open envelopes etc. If you have already done some training for self defense with another knife, then it will have to be your call as to whether you need a practice model or not. Some very experienced martial artists who practice using a knife for self defense use trainers. The trainers are essentially identical to the regular models, except the blade isn't sharp and there is no sharp point.
When you ask questions of the forum, it really helps if you can add some details that apply to your question. Especially if asking about a specific model, we really can't advise you well, until we know the uses you plan for the knife. Just asking if a particular model is a good knife is not likely to provide you with anything other than opinions. Hopefully, if you ask a question, you're interested in some facts.