Why kill and pin "bugs" if you like them?

My son Lukas is baffled as to why I carefully remove most "bugs" that enter our house and set them free and also tell him to be very gentle with ones that we find while exploring, but that I kill my favorite critters and stick pins into them. He knows that the pat answer is that I kill them to turn them into specimens, but like a lot of people, doesn't really understand why. There are many reasons, but this picture of Coastal Tiger Beetle specimens shows some of them. If you look closely, the patterns look very different from one beetle to another, so you can imagine that even a very good picture of one live insect might not be identifiable to species, as many times this is only possible by examining tiny characteristics through a microscope. Also, these are relatively large beetles, whereas some beetles get down to less than a millimeter, or around 1/50th of an inch, for the entire beetle and others can only be told apart by examining their genitalia, which it is usually not possible to examine on live specimens. Besides this, sometimes what is considered one species today might be split into 2 or more next year (say that all of the ones with less patterning were judged one species and the ones with more patterning were deemed another, or the two new species were told apart with some feature not available in a picture), and so if there were no specimens to reexamine, a record of a certain species would be meaningless then without a specimen to refer to. Another reason is that "voucher specimens" act as a permanent record of observations, so 50 years from now, someone could look at these specimens and they would be able to know from the labels that they were caught on a certain date at an exact location using a certain method in a certain type of habitat, whereas if I did not turn them into specimens, that possibly-important information would probably not be available to anyone. Yet another reason is that once I've identified a certain specimen, it becomes the ultimate reference to compare to when I find another one that may or may not be the same thing. I very much agree with the quote from Jane O'Donnell: "If a picture is worth a thousand words, a specimen is worth a million." There are no field guides that cover most insects, as there are too many of them. For instance, there are over 4,500 beetles in FL and around 12,500 insects. If you ever find a field guide for even the beetles, please let me know. :) Again, sorry to ramble, but I wanted to make it clear that most of the time, "bugs" need to be killed to study them and that there are many good reasons to turn them into specimens.