The topic of whether people are collecting or speculating can get heated very quickly in certain areas of the community.
While "speculating" is often characterised as a slightly grubby, obnoxious, commercial activity, that is solely motivated by the chance of creating financial gain, "collecting" is often described with more romantic notions, as if it were somehow a more noble pursuit, motivated by pure affection for comics.
The reality for most people is that they combine elements of the two. There are people who buy comics purely out of love for the story and characters, without any interest in what might happen to the price of those comics in the future; but they're increasing rare. There are also people who are only participants in the comic market because they see the chance to make a quick buck, but there are better opportunities to make money, so they are also fairly unusual.
What is much more common is that somebody is interested in comics, and starts buying them, progressing from reader copies to variants of one form or another. They may sell a few comics along the way, realising that they could support their increasingly expensive hobby in this way, which increases the frequency with which they buy and sell. Gradually, their targets are set on higher goals: moving away from the froth of modern comics, towards rarer Silver or Bronze Age keys, in higher grades.... and so on.
The reason to examine this is that it is important for a participant in the comic marketplace to understand for themselves where they stand. Once serious amounts of money are at risk - which can happen with surprising, if people get carried away - then it's important for your peace of mind to be honest with yourself about what you are doing, and why. The market can move fairly rapidly up and down, and for most people, having a significant investment into comics books can be a stressful experience - unless they've already come to terms with the volatility of the market, and the potential for loss.
Maybe that 9.8 signed slab of The Dark Knight Returns #1 is going to be buried with you, and in the meantime is proudly displayed on the wall of your house; so you're not really bothered if its market price doubles or halves. Or maybe you've speculating on a 1:1000 signed copy of Brzrkr #1, at significant cost, in order to sell it in a year's time to pay for something else - not necessarily the best investment in my personal opinion, but you've made a plan, hopefully you've assessed the risks against the potential return, and can manage the potential downside if it comes to it.
Suddenly finding that a significant portion of your wealth is tied up in comic books that are now decreasing in value can be a disconcerting experience, just as much as finding that they are all increasing in value can be somewhat exciting.
The other reason to know whether you are buying something as a collector or a speculator so that you know what your exit looks like. A collector might never part with something, unless it is perhaps to upgrade it to a better condition copy; a speculator should be clear with themselves that when the comic has hit a particular target (the trailer for the movie has been released, or the fair market value has gone up 50%) then it's time to sell and move on. It is very dangerous for a speculator to develop a collector's attachment to things, as you may then never part with things, and so never realise the purpose of being in the market in the first place. This becomes particularly dangerous if you're speculating without a plan, as you might keep holding a book, long past the point that you should have sold, only to find that its value starts falling.
We have made a lot of these mistakes ourselves, so this is the voice of some experience; at the same time, we've made good money from buying books below market value, and flipping them, which has enabled us to afford some of our grail books (I haven't my signed 9.8 DKR #1 on the wall yet, but it will happen at some point!) We have books in either our collections - unlikely to be sold, but maybe - or as speculative plays, waiting for the right moment so sell. And we also have books that we might sell, at the right price, but if they never get there, we're happy to hold them in our collections. But the point is we know which are which, and why we bought them in the first place!