It takes a different lighting procedure. When I light the torch, I turn the torch gas valve on just a little bit and aim the tip towards a shielded area and then strike a spark. It lights easily with a small flame still hugging the tip. Then add a small amount of O2, keeping the flame at the tip. Increase the LP and then increase the O2. If the flame walks away from the tip, just reduce the O2 a bit until it comes back to the tip. You never get the dark smoke that burning Acetylene produces during lighting. LP gives a cleaner burn.
I have used LP and O2 for more than 50 years and about 2 years ago needed to replace my hoses for the 1st time. My Smith regulators are still original. For working with steel up to 1/2" thick (bending or cutting) I get enough LP coming off a 20# BBQ tank even with the newer valve. I do have bigger LP tanks available, but have found their bigger size and weight to be an inconvenience. I also have a LP blacksmith forge requiring only LP and no Oxygen. It is naturally aspirated, single burner. The local farriers use 2 burner forges with BBQ tanks for supply.
I will agree that there are some metal working processes that are better done with acetylene +O2. But for the few times that I have needed or wanted Ac, it is not worth the price for tank purchase or rental plus the cost of the gas. LP is a bit different, but far less costly.
Paul in MN