I could go either way on a bike. Conversion or commercial e bike. Each has their advantages.
The commercial bike is plug and play type riding. No hassles or planning and insurable with easier resale to upgrade. Disadvantages are higher cost, less DIY maintenance possibilities and fewer upgrade options.
The DIY bike gives multiple options for powering a bike, allows customization of programing, is cheaper and can be made more capable. The DIY option is more limited to the mechanically inclined, may be un insurable and may have questionable resale value.
Five years ago when I built my first e bike, the commercial choices were unrefined, expensive and pathetic on performance and range.
I have since built a dozen e bikes. My first e bike build was a sweet little bike for my wife that looked commercial, was 750watt mid drive, 360 watt hour battery and weighed 38lbs. My personal bike now has gained the pounds as time has gone on. It is now approaching 80 lb. The bike started out around 53lbs. The bike is still way more capable than you can buy commercially.