The worlds bulkiest multi-tool might get you through a very minor bicycle repair, if you've got a separate multi-driver. Counting on one to be much good in an automotive breakdown is nothing short of full-stupid. A small set of Channel Locks, a set of side cutters, a 6" Crescent, and a multi-driver trumps a multi tool every day of the week. Thats what I keep in my house and I still end up running out to my car pretty regularly... where I keep that, plus a 3/8 ratchet set, a few more sizes of Crescents and styles of pliers....
And when I'm working on my car I still end up borrowing tools out of my truck where I have all that plus, 1/4 and 1/2 ratchet sets, Metric and SAE combination wrenches, snap-ring pliers, filter wrench, screw driver set, pipe wrench, pry bar, ball peen hammer, scrapers and picks ETC. I mean, I even with a few different types of pliers in my car, I occasionally need to go get something stupid like a long-nose, 45 degree something-or-other, so theres a pretty good chance that a Leatherman wont have you covered even just for pliers.
Recently I was doing some fairly basic work on a 2002 Honda Foreman, pretty much one of the most stone-age machines still in regular use... and even with all that crap in my truck I STILL needed to go dig around in my tool shed for a few odds and ends that I didnt have in my truck... all of which is to say... If you've got a Swiss Army Knife, a flashlight, and a Bic lighter in your pocket, you've already hit the EDC point of drasticly diminishing returns.
Especially around home or in a vehicle, where space is not exactly a comodity, I cant come up with a single good reason to be counting on a Leatherman to potentialy do you any good.