I appreciate all your advice and concern, I'll explain my reasoning a bit.
I have carefully considered options, hence the rather specific question.
Basically the for cooking options are:
1) No extra equipment. Rely on cafes, albergues, etc. No extra weight. Probably perfectly ok. This is the "Default setting".
2) A plastic cup with a lid that can be used in a microwave or with available hot water. Is it really necessary? Will double as a cup for shaving, brushing teeth, etc. Can put stuff in it, so the space isn't wasted.
3) Immersion heater (+ a cup). I haven't found a decent electric coil where I'm at. The ones I have found are either very big and heavy or look very rinkydink and, honestly, dangerous.
I haven't used a coil for decades, but I have a vague memory that they require caution and that a ceramic cup is probably the best option, since it doesn't melt like plastic or conduct electricity like metal. Ceramic is heavy and I don't probably want to carry it. Enameled metal? Will have to dig deeper.
4) Metal cup + a little stove. Metal can't be used in a microware but can double as a small pot.
I'm probably not going to use the stove a lot (if at all), but it might be nice to make something hot on a beach or similar on a nippy day. I do it regularly on walks at home. No-one has died, zero fires started. I don't use it indoors or near a fire hazard. Pretty much don't use it around the people anyway.
Options :
- Alcohol. DIY or ti stoves are small and light, fuel is easily found, but it's probably the biggest fire hazard of these and I wouldn't use it much, hence I don't really want to carry spirits. I've built and used alco stoves extensively when hiking and although relatively safe when handled properly, it's relatively easy to knock the thing over and that's when it's no longer fun and games.
- Gas. The stove isn't too heavy (mine is about 75g), cannisters are easy to find (Decathlon) and cheap at 4€ but sort of heavy at >200g. The 400ml decathlon steel cup (120g) is perfect size for the tiny gas cannister, should anybody care. (It's a tight fit when turned upside down. Don't push it in all the way, put the stove in bottom of the cup to make it stop.) The weight adds up though.
- You guessed it, Esbit. I have the tiny 14g titanium folding gadget (calling it a stove feels a bit much), so carrying it is pretty much "free". Add a foil wind screen and a light mug and done. Fuel is inert (actually a bit hard to light.) A packet of tablets weighs in at around 80g and costs 4-6€. This should be anough for up to 10 cups and gets lighter when used up. Since fuel can be found, it seems like the best option, should I decide to carry.
Tincatinker:
YouTube is full of people
Yup, how does that justify taking an unnecessary fire starter unless it’s going to significantly adjust your survival opportunities
It's not a justification for carrying anything. I was hoping to skip typing out all of the above by suggesting that if anyone wants to see a middle aged guy rambling on and on about stoves, there's plenty of high quality content available on the forementioned platform. Also survival is, hopefully, not a question. The best outcome here is probably a hot cup of tea and some noodles on a nippy day on a random beach somewhere.