Shy, the horizontally opposed Lycoming / Continental is a crude old engine, just like all but the latest generation. Same technology as an old Brit motorbike!
There's nothing magic about them that requires different engine handling to those other types. Toggle mag switches would work perfectly well (and do in the Citabria and Cub, just two such horizontally-powered aeroplanes I have extensive experience of which use toggle switches). Why should a C150 or a PA28 be different?
I'm quite well versed with the Lycoming. I'm an ex-RAF QFI and used to instruct on a UAS equipped with them and I was also the Chief Ground Instructor of same.
Why should they be different? Because the designer/manufacturer decided to make it so. If you don't like key equipped aircraft you don't have to fly them. I don't like them either, despite having learned to fly in them in my youth, but it's irrelevant.
My point is, if the aircraft you're sitting in isn't equipped with your preferred toggle switches but a rotary one instead, you really should follow the manufacturer's procedure, not your own based on experience from other types. The "dead cut" check is done for safety reasons. If you don't do it correctly, someone else could get injured.
JO,
Thanks, from what I've seen on forums, discussing problems with ignition on Rotax engines it appeared that these can fail due to power supply wiring external to the engine driven part. Unlike a traditional magneto, which has only external HT leads and a grounding lead to "switch it off".