Nearly but not quite. They do different things with some overlap.
A straight cutting (non profile) normally has a bearing the same size as the cutter at either the top or bottom of the cutter. If the bearing is following a template the cutter will trim the work exactly to the template provided that there are no internal corners with a smaller radius than the bearing. A bit with a lower bearing (flush trim) cannot plunge into the job. The primary exception to the same size bearing and cutter is rabbet bits, where you deliberately use a bearing smaller than the cutter to produce an offset cut.
Using a template guide allows you some more freedom, like plunging with a profile bit, but at the expense of being forced to deal with offsets.
Because the template guide must be clear of the cutter parts it encloses in its cavity, and must have some wall thickness for strength, the outer diameter is normally at least 1/8in (generally more) bigger than the cutter, so to make a template you must predetermine the cutter diameter, the guide diameter, calculate half the difference as the 'offset', and make the template smaller all round by the offset for external cuts or larger by the offset for internal cuts. Not too much of a hassle for straight cuts, circles or ellipses, but quite an issue for complex shapes.