I have never run into that option before, but I'm pretty sure I wouldn't pay 60% more for a deeper canvas. Half the canvases in my house are framed anyway, so the depth isn't apparent.

I did not like the .75 canvas frame and changed to 1.5”.

I personally like the larger depth frames for large paintings, say over 3'x3' because the smaller depth frames tend to bend and not lay flat to the wall on all corners when talking about huge pieces. That being said, I would not pay 60% more for it.

The canvas depth comes into play for framing purposes. I recently encountered this when ordering a canvas photo print from an Etsy seller, when he asked if I preferred the 1.5" or 3/4". I'm glad he checked with me, as the 1.5" would have been much too deep for the frame I planned to use. If you aren't planning to frame your canvas, buy whatever size you prefer.