OK. I can have up to 8 snapshots, and each snapshot can control a myriad of parameters, but there are still only 8 possible sounds.
If you have 4 snapshots and 4 stomps, then each of the snapshots can have up to 4 additional FX added to them. That's 4 factorial (4 x 3 x 2 x 1) combinations of FX for each snapshot, PLUS each snapshot with no stomps activated. That means with just 8 footswitches, I can have up to 76 different sounds.
Example. You have a snapshot for lead. You've tweaked dozens of parameters in your EQ, Compression, Overdrive and Amp blocks for this snapshot.
Now you have four stomp switches. One for Chorus, one for Delay, one for Slapback Echo, one for Reverb.
Now you can have your lead tone dry, or with any combination of chorus, delay, slapback and reverb.
AND you can do that for the other three snapshots, as well.
This is powerful stuff!