I only see this as a problem when the baseline % is not known
For example in LE you can get things like 125% Critical hit chance multiplier (that basically means ~6.2% i.e. 11.2% since your baseline is 5% afair)
Ofcourse, there are ways to make the baseline up to 8%-ish so the multipliers get more value
Still, don’t think it’s a “malpractice”, it’s just a way to make things sound more attractive overall
On the other hand I would agree if they DON’T make the baseline % known