App mining is pretty useless. Even normal mining is useless. You maxed out as 10-12k hashes. It is only a few cents a day.
My computer is running anyway all time and this App mining is nor useful or useless for me, I don't think much about it, at now there is little interest towards JSEcoin but this may change in the future. This can be consolidation period before popularity even though seems to be stagnancy and fading.