Hey, that's not a 500, it's a 590.
Busted, lol. jk
Single-points are for shoulder guns. Lets you keep the arm handy when you need both hands for something else... it's pretty much the same as a two-point "tactical" sling.
I don't see where a sling is much of an issue on a HD gun, though.
And I was gonna say you needed a bayonet to consider it a true replacement to the M44 as HD gun of choice.
What's a HD gun without a 'sticker on it!?
I'm really considering a Mossberg 500 for my next firearms purchase (right after a K31.) The 590 appeals to me a lot, since it's already got an extended tube, has the handguard, and I love bayonets on guns. OTOH, I like the fact it doesn't have the ghost ring sights like the other 590. I'm cool with a bead. If I can put a bead on a clay or bird that's flying through the air, hitting a person with it... well, can you say "easy?" Maybe if I needed to shoot slugs at deer or pigs (or people?) at 100 yards, I'd consider the ghost ring setup, but I'd rather not want to rely on a shotgun, even with slugs, at that kind of range.
It's just the 590s are a bit more $$$$ than the regular 500... Extended tube/shortened barrel on the 500 and I'm happy. FWIW, I don't see myself REALLY needing more than 6 rounds in a HD encounter (according to my math, 6 rounds of 12 gauge 00B/slugs = 6 dead intruders), so maybe I don't really need the extended tube anyway.