Although BTA's are more common (I assume) and easier to care for, a good number of folks do keep LTA's. LTA's are moderately difficult to keep (of host anemones which are already considered difficult to keep compared to the majority of marine fish). Also, LTA's are not natural host to as many species of clowns as BTA's. So although fairly common for aquarists, LTA's are likely outnumbered by BTA's.