Yes, and Lich Bane increases your burst significantly more than Liandrys. In order to outdamage 600 AP Lich Bane proc with Q Liandry proc you'd need a target with 6,3k health (and arguably, even then it wouldn't outdamage Lich Bane, because the Liandry proc decreases in power with each tick of damage, but I didn't feel like taking that into account). That said, shroom Liandry will outdamage Lichbane against targets that have decent health.
Of course, it's important to note that when you actually do a burst damage, then Liandry is even weaker (If you AA-Q-AA for 60-70% of enemy health then Liandry proc is only burning those 30% remaining - no matter when you hit the blinding dart).
The biggest pro of Liandry in burst-damage playstyle is the 15 Mpen - it can potentially increase your magic damage output by 15% (rare case though, usually even against squishies it will be around 10% - but in some other cases, it can actually be significantly lower (even as little as 0% - if the enemy simply has less MR than you have pen already).
And believe me when I say I tried a lot of Teemo builds (over 1 million mastery).