Even if tax is not applicable for converting bitcoins into fiats, we must at least consider the exchange fees incurred for conversion. The only possible solution for this, having all type of merchants for ever daily needs. If there is no need to convert our bitcoins into fiat, we never need to worry about tax.
Even OP's concern is not this, the most needed thing for all the bitcoiners here must be spreading out bitcoin adoption. Till then, we may need to fear about government regulations /taxes /exchange fees and obviously high fluctuations of bitcoin prices.