If you didn't have any charging issues with the bike and understand the limitations of the charging system as it pertains to your particular riding style (a lot of city riding), or aren't going to add on accessories that require a high power consumption.
Put the battery on a float charger when the bike is parked in the garage .
I would say that you probably could have done without it .
I've got the stock charging system on my '81 R65, run PIAA40 driving lights, and other than having a set of brushes wear out at about 55,000 miles, I haven't had any issues with the charging system .
I've been asking myself the same question, if and or when something goes bad, would it be worth the extra cost to upgrade to the 450 watt charging system, or just replace the failed component .
From what I've seen here, the rotor and the diode board are the most common failure prone parts in the system .
Replacing each of those is around $100US each, from Motorrad Elektrik .
Looking at it from a financial stand point, you put $575US into a bike worth about $2000-2500 .
Just to show you what know, I put around $2000US into my '81 R65 about three years ago, after putting 85,000 miles on it !!!!!
An average person, would have thrown the bike away, instead of doing what I did

.
Nobody ever said owning and riding 30 year old motorcycles makes much sense anyway

!!!!!