i wouldnt say such a blanket statement.
aerial->shine-> away aerial is great cuz it keeps pretty u safe, but it also effectively ends pressure. the opponent is free to do whatever they want. Assuming they dont get baited into grabbing, they can wd back oos, jump and waveland on a platform and run away, wd foward oos and do a move, marth can jump oos and fair you etc.
Dont always assume your opponent is going to perfectly counter your sheild pressure every time so oyu should only do perfectly safe things like drifting aerials and such.
Sometimes, its more beneficial to go for sheild pokes when their sheild is low, or do aerial->dtilt to clip their toes, and even waveshining twice (omg teh horror) on their sheild can throw ther timing off.
Some things are inevtably worst than others, but you shouldnt always just do the safest thing, cuz the safest thing usually has a low risk-low reward payout. And again, dont just assume that if you choose a less safe option, your opponent s going to magically counter you, cuz they cant unless you over do it.
I should also throw it out there that its really important to note how your opponent responds to sheild pressure. MOST people have one, go-to option to get out. We make a deal about "mixing up" or sheild pressure, but majority of people dont ever really "mix up" their sheild escapes.
Lots of sheiks will instant nair OoS every time, many foxs will Full hop dair/nair a lot, or always shine oos. Many falcons will either always aerial OoS, or roll.
Just as important a smixing up your pressure, is taking note of how your opponent frequently responds, because then you can aim to specifically punish THAT instead of just "omg safest option all the time"
edit: lol this thread is moving fast. this was n response to anyone saying always late aerial, or always drift away on your second aerial etc