iMacs are basically laptops built into a display. You're paying a premium price for the laptop parts, but not really getting desktop performance apart from display size. I used to own a desktop Mac (one of the last tower-case Mac Pros), but when I went to get myself a new desktop computer a few years ago I built a linux box around PC parts* instead of buying another Mac. I just could not justify the premium price. Also, Apple seemed (and still seems) to be ignoring/abandoning the high-performance desktop market, even to the extent of bringing a lot of iOS (phone) bits to the desktop. I'm not a fan of dumbing-down the desktop like that, though other people seem to be ok with it.
That said, my laptop is an older macbook air, which I love. Email, web (incl. animeforums ), spreadsheets, powerpoints, etc. all do fine. I'm typing this on my laptop. Nothing wrong with laptops. I even bought a new macbook for my Mom a couple months ago for her birthday. For everything except high-performance uses a laptop is great.
(When I say "high performance" I mean mainly games. Though there's a lot of games that you CAN play on a Mac, there's a lot of titles that are PC-only, and you probably would not be happy playing many cutting-edge FPS games even if they are available. I have played both Minecraft and Kerbal Space Program on my macbook for example. They work, but only barely IMHO. I wouldn't recommend the experience. The newer iMacs have finally gotten a GPU bump with Radeon/Vega and can do a lot better than my old laptop, but that doesn't change the fact that they're still basically using laptop parts. They're way behind in what you could do for the same price in PC-land in terms of desktop computers, even at similar quality levels.)
Bottom line.. if you're not a "computer person" and just want something that works out of the box to get typical computer work done then an iMac is fine. If the price doesn't bother you and you don't need to play the latest-and-greatest games then you'll be happy.
(*990FX chipset motherboard, FX8370 CPU, 32GB RAM, Radeon RX480 GPU for only about $1k. Of course I had to build, install, and configure everything myself for that price so that doesn't include the cost of research, labor, integration, or mental anguish. YMMV.)