First off, the outer chainring isn't replaceable, it is swaged/pressed onto the crankarm. Only the inner ring is removable, so if you want to replace the outer chainring, you can't reuse the driveside arm.
And the crank has a Sugino Maxy taper, which IIRC only fits less-expensive (back in the day) Maxy-type cranks, so if you want to upgrade to a better crankset, one with both chainring removeable, you may need a new bb spindle as well, or maybe an entire new bottom bracket. Since your bb is noisy and grindy, it may need replacing anyway---at a minimum it needs an inspection/overhaul.
Not saying you should upgrade, and if you want to keep it stock you wouldn't, but just so you know it could also involve replacing the bb. FWIW, aside from not having to replace the entire crankarm the next time the teeth get worn, it's also nice to have both rings replaceable to give you gearing options to choose a different outer ring, bigger if you're a shtarker or smaller if you hardly ever use your current high gears.
The IIRC part of replacing/upgrading matters, because the area of my brain that remembered all that different spindle taper stuff, and Maxy-type chainring configurations, has been written over by my need to not forget the Gilligan's Island theme song ("...the Skipper, too. The millionaire, and his wife. The movie star!..."), so maybe there are replaceable-outer crankarms that will fit a Maxy taper?
As for whether to replace the outer ring, there is a theory that as long as you don't mind having to replace the entire toothed parts of your drivetrain all at once, you never have to replace any chains, cogs or rings until the chain starts skipping somewhere. The chain and teeth wear in together, and we usually only find out our teeth are worn when we put on a new chain and it skips. Often on the smaller cogs, which wear faster. So for some the answer is to never replace the chain. Till it all goes to heck at once.
In that scenario, a few chipped/bent/manked chainring teeth don't matter at all, as long as the chain doesn't skip and the front still shifts OK. If you look at modern chainrings, you'll find lots of weirdly shaped teeth, some shorter, some sharper, etc. Sure, that's done for a reason, and precisely designed by advance computertronics, and yours are random, but if it doesn't cause any problems, then it's not necessarily a problem. Those jagged ones are more likely to draw blood if you slip tightening something nearby and metal meets flesh, so there's that. You could take a file to the sharper ones and square/smooth off the the scary edges.
If you want to be a by-the-book mechanic, you replace the outer ring, in your case the driveside crankarm, and the chain, because after all this time it's suspect. Inspect/overhaul/replace the bb as needed. If your replacement driveside arm/crank has its own inner ring, use whichever one looks better. Then see if you have any skipping cogs in the rear. If you do, new freewheel. Technically, you may just need to replace a smaller cog or two, but finding replacement cogs these days is difficult.
And never forget, Gilligan's fans, it was supposed to just be A THREE HOUR TOUR! What the heck! Nobody expects to get shipwrecked on a 3hr tour! And, sure, maybe the Captain should have checked the marine weather forecast a little better before setting out, but, ya know, things happen.