Hi Bob. They get mixed reviews and I am not the guy to answer the questions with established credibility, unfortunately. But I have learned a few things researching this topic here and on other sites. The topic has been tossed around quite a bit here on the forum. I think there are quite a few considerations. Are you trying to improve the ability of others to see you? Are you unconcerned about night driving? LEDs might improve your conspicuity to others in the daytime while decreasing your ability to see others at night.
The combination of the reflector and the architecture of the replacement bulb work together. So, if the bulb does not hit the reflector properly, you may not achieve either result...being seen by others or seeing better in low light.
No. They do not last forever. They are a wear item but produce the same amount of lumens, generally, across the life of the bulb.
You may get fast blinking turn signals if you convert those bulbs to LED. But, that is due to the turn signal controller (can't recall what it is called). But, I believe they have an aftermarket solution that was discovered by prior posters on this site. There is no CANBUS on the NC700X. So those errors that you might get on an automobile by switching to LEDs are not present, in this bike, for the same reasons.
Yes, there is heat but most manufacturers of QUALITY bulbs manage it well through passive or electromechanical methods. Not to worry...generally. Fitment maybe an issue in either case.
Yes, you should bother if the bulb checks all of the boxes for what you are trying to achieve.
Remember, LED or not, you need spare bulbs. So you'll have to keep some h7s on hand or another LED in your frunk, wherever.
Cannot comment on which manufacturer is the best. But if you have an earlier model without the LED headlamp, I wonder if the NC750 LED will retrofit into the NC700. Might have been discussed in the past on here.
If you are trying to achieve conspicuity/increased visibility by you to others, you might look at Skene Photon Blasters. Stupid name. Outstanding product.