Why own a slot machine? There are lots of reasons.
Some slot owners have them because they appreciate the design and the ingenuity that went into creating them. The older purely mechanical ones are mechanical marvels. They convert the simple motion of pulling the arm into a spinning, whirling , nearly living thing that can accept coins, compute odds, and based on the final position of the reels, dispense the correct amount of coins to a win. Its a thrill to hear the coins clink against the tray , even if its your own money. The sound the machine makes as it quickly goes thru all the different stages needed to complete a cycle is really quite an amazing thing.
Some like them for their look, especially the oldest ones. the castings and paintwork are elaborately eye-catching, of course to entice someone to try their luck. they are appreciated as things of beauty.
Lots of people like the newer, solid state electronic slots. They may be familiar with them from casino visits, or just want a machine with more bells, whistles, and lights. They can be less finacky than the older games, and that appeals to people, just as the older models quirks are considered charms.
People that own slots are often ones who appreciate lots of coin op diversions, like pinballs,
arcade games, etc. In a room, they complement each other nicely.
Finally, some people like the "naughty" vibe of owning their very own one armed bandit.
Most likely , its some combination of all of the above.