There are scopes out there with no hardware serial trigger, but do have software serial decode, or the serial trigger only frames the packet and does not qualify/inspect the contents. Yet this thread is a mess of people not making that key separation which answers part of the question of the OP. You can talk about your specific situation and be correct, but stop making it sound like that is true for everyone and everything because it is not.
Even with hardware triggers that extract errors or specific data values/patterns, there is still dead time which can miss some events. In some situations that is important and cannot be replaced with deep memory, instead segmented memory can be the better choice, or a more powerful trigger. Long memory is not a replacement for short re-arm time.
I don't know of any current production scope that has software triggers (out of mainstream brands i know off). I certainly don't know them all naturally..
You seem not to understand what I want to say. Let's take example of my Keysight 3000T and Siglent SDS6000Pro H12.
MSOX3000T has faster retrigger rate in normal mode, no question. But it has 4MPts of memory total while SDS6000 has 500MPts and even more in segmented mode.
Which means I can capture 125 times longer capture at same sampling rate and just capture whole burst of data from sensor for instance.
And for data in that capture, there is 0 blind time. Zero.
With MSOX3000T I have to use segmented memory...
And I have to have very short blind time not to miss packets...
With sds6000 I don't have to use segmented memory most of the time. And if I do I get many more segments.. and blind time is minimal because in segmented mode it skips processing. In segmented mode difference is minimal.
Segmented memory is better for sparse packets on fast protocols (short packets, long dead time). Which incidentally makes short retrigger time less critical. No missed events.
For a burst of really fast packets with very little interpacket time, continuous long memory can capture tens of thousands of packets in single go. With zero blind time inside. No missed events.
As for decoding speed, on scopes with hardware trigger and software decode, decoding is asynchronous to capture. If decode is too slow to decode every screen refresh,
Short rearm time is (like I said) useful. If that is so important and if you feel that software decoding is slowing down retriggering ( it should not because trigger is hardware and decode processing is not included in retrigger time but in display threads), you can disable decoding, capture packets you like and then stop scope and enable decoding. It will decode it then. That is one great advantage of decoding as postprocessing. You can also grab some data and play with decoding settings until you get meaningful data. Compare that with MSOX3000T that you need to have all protocol parameters perfectly set before capture or it won't decode right and you have no other choice but to capture again...
And at the end of the day, I use both Siglent, Pico and Keysight and they are all up to the task, just by using different techniques.
That is one thing.
Other is this: If you are looking at scope interactively with packets flying by, hundreds per second, looking at the screen will show you just a bunch of changing data and waveforms.. You will see just a blur.
You need to either :
1. trigger on a rare packet that happens rarely enough for you be able to see, read and comprehend messages
2. Capture 100s of packet individually using segmented mode, stop and sift trough them. In which case even scopes with software decode don't do any processing and have extremely fast retrigger rates.. POI is very high on all.
3. Capture very long capture that has 100s of packets inside, stop and sift trough them. In which case there is 0 retrigger time between packets and POI is 100%.