Earlier quoted context omitted.
Cost as in efficiency. (Last time I looked, filaments were rated less efficient than direct light sources. However, they seem to become better.)
I'm using these [1] https://www.osram.com/ecat/PARATHOM%20Retrofit%20CLASSIC%20B...
What is it about your current bulbs or the filament design that makes you not classify them as LEDs? The power use looks the same and the listed CRI of >=80 doesn't inspire confidence.