Like you said it’s important to reduce noise during recording. It does build up when you have more pedals especially big digital ones. If you’re just playing with a few pedals and don’t notice significant noise you’re probably good for now.

I do think it’s a good investment if you plan to get more pedals simply for the fact that many of them have outputs that allow you to power bigger pedals or switch up to 18v for pedals that support that.

It might get bad if/when your chain has both analog and digital pedals. I have more ground noise in my recorder/mixer (through the AC outlet) than on my pedal chain tho :/

In my experience, I only run into issues if multiple devices are on different circuits of the main AC grid.

So if I have my amp plugged into an outlet that goes to one circuit breaker, and my pedal power supply plugged into a different outlet on a different breaker, there’s noise. My guess is that there’s a slight differential between the grounds of the two circuits. Unless there’s a ground lift, most equipment joins together the grounds on the input, output, and power. So if the grounds are at slightly different charges then you get a voltage from one to the other, which causes the noise.

Practically speaking, just putting all your pedals and amps into one surge protector fixes this. Unless you have some really weird tube pedals or something, pedals have a negligible amount of power draw.

The other benefit of an isolated power supply is if a pedal has a momentary large power draw. Quality pedals have an input capacitor (basically a reservoir for electricity that deals with small irregularities), so that shouldn’t be a problem, but with older or cheaper pedals it’s a possibility.

If you run into noises or dropouts, try using a 9v battery instead. You can even get a real cheap adapter if a pedal doesn’t have a battery compartment. If that fixes it, you could just use a cheap power supply and deal with batteries for any live gigs. Depends on how often you gig, how many pedals you use, etc.

Get a used one on eBay! Good linear power supplies are super old tech and are super robust.

Some pedals draw power more unevenly then others, which can cause a “buzz” on the power supply output. If it’s just one supply and one pedal, and it’s designed to work with a little buzz on the supply, you won’t notice it. But impose that buzz on other pedals with shared power, and the buzz might make its way into the audio signal path. Isolated supplies let pedals do whatever they want with their own power supply channel, and the power stays clean to the others.

Ultimately, you don’t need to solve problems you don’t have. If you try sharing a supply with your pedals, and they work well together, then they’re is little benefit to an isolated power supply. A power strip of power supplies is a totally valid way to have isolated supplies, too (albeit harder to manage and might be less space efficient).