Why are billiards played on a pool table?

During the nineteenth century, off-track gamblers would often play billiards
while waiting to hear the results of a horse race. Sometimes, if they
agreed on the merits of a particular horse, the gamblers would pool their
money in an effort to win a greater amount on one bet or to soften the
blow of a loss. The “pooled” money, both bet and won, was counted out
on the playing surface of the billiard table, which the gamblers came to
call their “pool table.”