Refwalk explosions are not so bad if you know how to use them eh ...
They're pretty bad in crowded areas. I haven't yet tested them in New Vegas, but when I tested them in Fallout 3 they reduced my frame rate by over 50% when running at 1 iteration per frame, which is more often than I would expect them to be run but still enough for them to introduce noticeable stutter. Decreasing the explosion radius could reduce this effect, but would also reduce the effective range of whatever you're trying to do.
Looping through references via
NVSE's reference-walking functions also allows access to non-actor references, and dead actors.
It's certainly good to think about how a feature could be implemented without the use of the script extender - I think that thinking about different ways of doing the same thing is always going to be beneficial - but I tend to treat script extender functions and vanilla functions the same when modding, in that I won't avoid the script extender functions if I can see a benefit in not doing so.
It's also worth noting that there are fewer users of New Vegas that cannot use
NVSE than Fallout 3 users that cannot use
FOSE, if I remember correctly.
Cipscis