Oh goodness... I wouldn't have much of anything if I didn't collect things. My lamps, furniture, kitchen ware items are all what I consider collecting.. I have old pots, pans, skillets, every possible old type of kitchen utensils & small appliances but I use them (most of them at least) so it goes beyond collecting as I use these items. Most have value beyond what new junky stuff would cost & are of better quality than most new stuff.
Almost every lamp or ceiling light globe I have is vintage or antique & things I got because #1 they had value & #2 I liked them but at the same they also serve a real purpose. I'm going to buy that kind of stuff anyhow so why not collect that stuff cause then again it's almost not collecting.
Id say the only things I collect that serve no real purpose are #1 uranium glass (preferably vaseline & jadeite but some green depression too) & #2 COINS like you! I have a nice collection going on but I look at them as an investment for the future if for no one else than for my daughter when I'm gone. I collected football cards as a kid & I still have those but I don't collect them anymore & I don't think I would part with them, not yet at least.
I do collect some Asian/Oriental items & furniture that some serves a purpose & some is just for decor or show. My dining room is done in all Asian decor & furnishings. My Kitchen & 2nd bedroom are completely art deco-ed out! My living room & bedroom is a mix of mid century, contemporary & art deco. My 3rd bedroom & back screened in porch art art nouveau - arts & craft era. The man cave in the basement has what most man caves would have & a lot of it is vintage & has good value.
My point is I actually collect a lot of things but I collect a lot of necessary things like I listed. One trick to collecting most things like I do is to get rid of something if you get something different or better to replace it with & that's where hoarding & collecting differ to me I guess.