Plugs can develope slow leaks over time and must be redone. Not often but it does happen.
Patches leave the ply area inside the hole open to water that can corrode the steel wires that the plies are made of. This can cause a weak spot but generally the tire is worn out before it will become dangerous.
Large holes that are just patched can offer the opprotunity for water hydralic damage from driving at high speeds over very wet roads. This can lead to the above condition only faster or cause a tread seperation.
The very best is to use a patch that has a plug in its center. The plug is pulled through as the patch bonds to the inside of the tire. Tubeless tire repair for OTR trucks is done with these types of plug-patches.
The best,imho, for home, are the solid rubber plugs properly installed. I mark the rim inorder to locate the plug for inspection if a tire is ever found running low air pressure.
I do not care for cord type plugs but have used them with success.
Tube type tires, like most spoked wheels use, should have the tube patched/inspected and the tire must be patched to prevent water from entering the tube/rim area. This water will cause the tube to bond to the tire(overtime) and cause the rim to corrode, be it steel or alloy.
Street M/C tubes should never be patched twice.
I did not check any pole.
