Analogue (as opposed to outboard; you could have an outboard digital limiter) limiters simply aren't capable of the type of brick wall limiting that is typically desired at the end of a mastering chain - there will always be some overs. Software limiters are capable of look-ahead, which allows them to see the audio before it happens and prevent clipping. Although it's technically possible to implement something similar with an analogue compressor the sound would generally be much more coloured.
Put simply, digital limiters generally sound more transparent than analogue ones, and transparency tends to be the characteristic that MEs most desire in a limiter.
whatever works. that's my philosophy. there are countless threads where people discuss x limiter being better than y, but think about it? what really counts? the equipment, the ideas, or what you do with it?