Reasons to add salt when boiling pasta

Cooking recipe books may recommend adding salt when boiling pasta. At this time, it is often stated that about 0.5% salt is usually added to boiled water. (Generally, the preferred salt concentration in cooking is 0.8% to 1.0%.)

【cause】Add the seasoning of pasta.The pasta is finished in an elastic state. (Prevents the outflow of salt added to dried noodles) 
③ Suppresses gelatinization of starch, reduces exudation, and reduces sticking of noodles.
A common mistake is to raise the boiling point of water.
However, when about 500 g of pasta is boiled in a little less than 6 liters of boiling water, the boiling point temperature that rises when 20 g of table salt is added is 0.007 ° C. The boiling time has been reduced by only 0.5 seconds.

From here on, it's subjective.
② and ③ in the above article may be scientifically so, but I think that you do not have to worry about home cooking.
Also, if you add too much salt and it becomes salty, you should wash the boiled pasta noodles with hot water.
Reference material  料理の科学① 総合調理科学事典 マギーキッチンサイエンス 味のしくみ