As clearly a trained person how accurate are they , Do you have to regularly watch the flame while you work , does it just go out or do different things according to what is present ?
They can be quite accurate BUT it can take a lot of time to get into using one correctly. The coal industry had fabulous training schemes to gradually build your skill levels in such things, plus as an official, you had to re-train every three years and be tested (along with your first aid and hearing).
Sinker will have been trained in such (as was I) but skills fade with time as well as eyesight. For most casual users the critical thing is whether the flame is still alight and/or if it will re-light. For explorers use, finding methane is very unlikely so the need to read flames is a dead skill really.
Couple all that with the problem in obtaining the correct fuel for a lamp (colzalene, although you can use lighter fuel), it is probably better to use your lamp as an ornament and buy a gas monitor!