For use at home, there's no question that separate keys are more useful and more economical.
A multi-tool has limitations that make it cumbersome to use in tight spots because all the keys are attached to the tool. Separate keys suffer no such limitation.
Separate keys can be bought and replaced individually and very inexpensively -- not so with a multi-tool.
I wouldn't buy the ridiculously expensive set of keys you show in your post. Just buy the keys you actually need. Drop by any local hardware or automotive parts store and buy the hex keys you actually need. They are inexpensive and should last a lifetime as long as you don't buy the cheapest thing they have. Like all tools, it pays to buy quality. Although you can buy them online, I prefer to buy tools where mechanics buy them. Automotive supply shops such as NAPA in the US are usually your best bet. They cater to mechanics so they won't sell cheap crap.
Torque: There's no way you'll ever produce correct torque with a multi-tool unless you're an experienced mechanic who "knows by feel" from thousands of repair jobs. Individual wrenches are also longer and give you more torque than a multi-tool. If you need even more torque in order to remove things like pedals, you just use a bit of pipe to add leverage. I keep a narrow piece of steel pipe about 12 inches long in my toolbox just for this. You just slip it over the long end of the Allen key and it gives you all the torque you'll ever need. Some people prefer the wrenches with plastic handles attached such as those made by Park Tools, but that's purely a matter of personal preference. I prefer plain wrenches with no handles on them since the handle means it can only be used in one orientation, not two like a wrench without a handle.
Losing them: My set of Allen wrenches dates to the 70s. I don't understand how you lose tools from your own garage.
But on the road? Yeah, sure, I carry a multi-tool like everyone else; but your question was about home use.