You all know that incandescent lamps barely produce longwave UV. So i don't know why these blacklight incandescent lamps were producted and still producting today (Although rarely). Many companies trys to overdriven the filaments of blacklight incandescents at the expense of the life to increase the uv output, but this is still not enough. Israel country aware of this and completely stopped the importing of incandescent blacklights. All blacklight lamps imported to Israel are: Fluorescents in all types and mercury (Blacklight mercury lamps are for public shows).
By the way. When incandescent blacklights were still here is Israel, i even saw a tubular version of them in small, low cost bug zappers.

These "blacklights" rather emit a dark purple light. I have a couple, and they won't make white things glow like real blacklights would. I personally consider them as colored lamps more than blacklights, but they're still cool!

Same here,I consider these more of a coloured lamp rather than a effective blacklight.

These lamps can't be used as a coloured lamps because they are as dim as a real blacklight blue lamps. Coloured lamps should be more bright for their applications. Also, coloured incandescent lamps, unlike fluorescents and metal halides, are designed for external hanging decorative lamps (A larger but similar style of the christmas lighting). Still these incandescent blacklights would not be suitable for this.
The dark purple light of blacklight incandescent is in the fact that the wood glass allows only the deep blue and violet and the deep red of the visible light to pass. This lamp may look as suitable for dark rooms because of its similar intensity to darkroom incandescents, but because there is a blue and violet in the spectrum, it will not suitable.

I also have a incandescent black light, it can make (fluorescent) highlighter ink glow, paper could (slightly ) glow, and same with cotton.