New User Intro.... Mulch Kit Q

Hello all, I have been a reader of the forum, but never a member until now.

I just purchased a Gravely ZT50 and this is my first ztr type mower. It is replacing my seized Cub Cadet LT1045, I kept her running as long as I could, but eventually that Kohler Courage couldn't go any further, but I digress...

I live in South Florida, and have an acre of St Augustine turf. I ordered the mulch kit for it, but the dealer was out of inventory and had to order the kit. They asked me if I wanted to wait for the kit to come so they could install it and then deliver it to me. I opted not to wait because my yard was getting very thick and needed a cut. My new mower arrived this morning and I was anxious to try the thing out and do a cut. I set my blades to 4", and started mowing. I was amazed that I did not see any clumps of grass in yard without having a mulch kit, and I am wondering now if I really need the mulch kit. St Augy grass is very thick stuff, and I am not sure if it is better or worse for a lawn to mulch or not mulch. I am assuming the mower prefers to not have the extra load of mulching if possible. Your thoughts?