Since you don't consider weight to be a factor, I'll move on to the secondary reasons I tarp. The significant weight savings was the main reason that made me consider it. I do most of my trips in Calfornia and have to deal with the Sierra Neveda and it's legendary hoards of mosquitos so bugs are a issue that I have to deal with.
A tarp is easy to set up during the day to get out of a rain storm while you eat or rest or if you just want some shade. It is less a problem to deal with when wet since it's smaller. There is no inside floor that needs to be protected from getting wet. You have just a ground cloth/bivy that is packed up before the tarp comes down and it's easy to keep the top dry. A tarp is just a single sheet that is easy to lay out and dry quickly when the sun comes out.
I am really lazy. I don't even bother to use my tarp on most of my trips unless the weather calls for it. I camp out in the open or in a bug bivy for bug protection. It is easy and fast to set up camp if you aren't setting up a structure that isn't needed. I don't mind carrying something that only weighs a few ounces that I may not use. My MLD bug bivy gives me enough space to read or write. It works for me since I don't like sitting inside a tent for long unless I'm sleeping. I'd rather be outside as much as possible.
MLD's Grace Solo tarps are larger then some other manufacturers solo tarps. They offer an extended length if you need more security from rain. I've weathered hard rain and snow in mine with no trouble. It's easy to cook under one. I've never sat under one for more then a few extra hours waiting for the weather to clear. If the weather is going to rain all, day I will not stay under it all day so the smaller size isn't an issue. Instead I'll hike in the rain or I would have planned my trip to avoid such weather if possible.
A smaller tarp does take more skill to use efficiently in weather, but it doesn't take long to learn. I started with a silnylon 8×10 tarp that I quickly decided that I wanted a lighter and smaller one.