That work is really impressive and quite frankly I'm in awe.

Now that you've done the lion's share, it's probably a moot discussion about buying that blade. However, you might have worn out your existing one and if you're ready for replacement the actual cost of the new carbide one is not $136, but the difference between the standard blade and the $136. Considering the overall time/effort and expense of projects, it may be worth it if it makes the job easier/better?