these were all torn out of Idaho state maintenance buildings with multiple 16' tall roll up doors. they had too many complaints of not maintaining heat during winters. they ripped them out years ago, and installed the separate hanging units. i kinda wish i kept a section of one of them for my own shop though.
I mentioned the roll up doors can be tricky
That said, think about this... Garage is heating to 55F with a unit heater. 16' roll up door is opened and it's 15F outside and windy. We all know what is going to happen to the inside temp when that garage door is opened.
Close the garage door, you might have a 35F indoor temp in the conditioned space. With a conventional 80% unit heater, you will now have a decent run time to bring the temperature back up to set point. However, with radiant heating, if properly laid out and sized correctly, once that roll up door is closed, you're back to feeling the heat instantaneously.
Radiant tube heaters are more expensive than conventional unit heaters (and can be more labor to install), but they will save you more on the fuel usage, and if laid out properly, feels much nicer than forced air. The added reality is if the tube heating isn't laid out to where people are going to be, no one will feel the heat (this is where size and hanging height of tube heater comes into play).
That said, unit heaters are less expensive and more "forgiving" per making a mistake if that makes sense. Just oversize it LOL
