What about that moonclips "tend to be bulky, turn rounds loose at inopportune times and . . . get bent in ways that can tie up the gun."
"Coming Around Again" by Tamara Keel in Shooting Illustrated Jan 2023
In addition to what mcb said, not all moon clips work with all brass for a given cartridge. The base and rim design of cartridges varies from manufacturer to manufacturer.
I know TK Custom sells two different thickness moon clips for different brands of 38 Special cases. One if for RP, Starline, and one or two other brands and the other is for WW and a few other brands.
Also, for my S&W 610, The moonclips I got at first did not work well with the 10mm cases that I have, all WW, but did with 40 S&W. I got a different brand of moonclips that works with my 10mm cases.
I think the 45 ACP and 9x19 moonclips are not as particular. I've had fewer issues using odd cases with my moonclip ammunition for these revolvers chambered in these cartridges.
But, once you find a moonclip that works with your cartridge, your good to go.
I have three S&W 38 Special J-frames modified for moonclips as well as revolvers that use 10mm, 45 ACP, and 9x19 ammunition. I'd rather carry moonclips for reloads than speedloaders but the moonclips do require some protection while carrying to prevent damage. There are a number of modes that can be used for that.