Ethyl Maltol can sweeten/soften sharp flavors in liquid, especially tobacco absolute.Ethyl Maltol acts as a buffer more than a sweetener IMO, although in greater qty it will add sweetness. It is normally dissolved 1/4tsp in 10ml of PG and used at 1-5% by some folks.
I use it to take away the "dryness" felt with all tobacco flavours at 3%. It rounds out the vape without adding sweetness perse.
With fruit flavours it is known to take off the edge/sharpness of certain flavours. That is why I call it a buffer rather than a sweetener.
There is no need to dissolve it with PGA or alcohol. I believe this stems from folks mis-interpreting the proper dillution of TA (tobacco absolute) which does in fact need to be diluted in PGA for total suspension. TA diluted in both PG and VG separates after time. Depending how strong a tobacco flavour you like, TA is disolved at a ratio of 1-4 drops per 10ml PGA.