I'm a cheapskate so I'd probably make a shortcut so I can say "siri, log my weight at 165 lbs" and have that put my weight into apple health or a spreadsheet. It's a bit more friction, but if the data is useful that's what I'd do. If I find that I'm not using the shortcut, then the data probably isn't useful.

You don’t even need a shortcut: “hey dingus, log a weight of 156.3” and it gets logged to HealthKit. Just did it minutes ago (because I long ago gave up on getting that Withings scale to do the same).