An intuitive explanation as to why a matched filter is time reversed?
Picture the transmitted signal as a «signature». You want to find some process that maximize the probability of detecting that signature even when there is noise.
What do you do to find some signature buried in noise? You make a template that exactly match the known signature, and you slide it back or forth in time, noting how much the actual signal deviates from the ideal template in any one spot. The time-shift that gives a «large enough» correspondence is your assumed signal location.
The time-reversal of the template is just about reversing the reversal of that argument in the convolution operation. Think of it as non-reversed correlation if you prefer (leaving out complex numbers right now).
-k