The Sun, Part 1.

Some of these points may be part of the reason. Reflectors tend to be of larger aperture due to their "bang for the buck" advantage. A larger aperture is of use in light-gathering ability - not a concern with solar observing. A larger aperture also can enable better resolution. But with solar observing, resolution is severely hampered by the heat environment - daytime observing of a hot object. Also Newtonian and Cassegrain reflectors with their open tubes can be subject to problems with resolution degrading air currents. Refractors as well as compound reflectors (Schmidt-Cassegrain or Maksutov) with their closed tubes are less subject to this effect. All this means that a much smaller, easier to handle and perhaps less expensive refractor will perform as well as a larger reflector. Another important advantage is that a smaller narrow-band filter will be much less expensive.

Not at all, Richie. Just get a sheet of Baader Planetarium Solar Continuum Filter. Its much less expensive than pre-made filters. Here's an example of a filter I made for a Celestron-8.

C-8 with Baader Planetarium Solar Continuum Filter used to Observe Transit of Venus

The filter cell was constructed from some heavy poster paper and glue. Like a lot of things in astronomy, there are advantages and disadvantages with whatever equipment we may have. Sometimes the disadvantage may be so severe as to preclude using some equipment for a particular purpose. But I see no reason to avoid solar observing with a reflector. Just compensate for its weaknesses.

There may be some issues with the sunlight directly heating the tube, but the mirror ​must​ be shielded from the Sun's rays by the filter. It will suffer from little extra heating due to observing the Sun. You might be wise to employ some sort of fan to evacuate warm air from the tube like employed in night-time observing. Do a web search for "cooling fans for reflectors". One advantage of solar observing is that the air temperature is usually not falling like it is at night. So the mirror's temperature will likely be near that of the air, contributing to sharper images

Be sure that if you get a solar filter to fit an eyepiece that you don't allow unfiltered light from the main mirror to fall on the eyepiece and filter. To do otherwise could cause the eyepiece filter to crack from the heat, let alone destroying the eyepiece, camera or worse yet, your eyesight. The safest way is to use a full aperture filter or an offaxis mask and smaller filter for the main mirror.

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Best Regards,
Russ