Kind of - I don't see it

Or you may try to think bigger and tor that extra weight use bigger engine. In example somewhere around 40cc or 35cc on glow might weight the same as 25 with magneto. Extra power never hurts as long as you use throttle stick instead 'throttle switch'

I didn't find glow ignition on gas engine any less reliable than ignition-gas.

The main reason is the same, why we got a gas engine in the first place. Gas is just cool. As long as the plane carrys on-board glow battery you work with this engine exactly the same field equipment as electronic ignition engine: Fuel the plane, flip the switch and flip the prop.

And the last thing is that the engine (my 25cc ) costs 25 dollars, when any decent size glow almost 10 times more.

If you are Bill Gates, not problem for spending a couple hundred dollars. But if you work for living, then the hobby gets what's left.[&:]

I would rather say, enjoy your hobby, not kill yourself with it.

RysiuM