At the cost of a level 3 slot, yes.
Compared to greater invisibility, (level 4 slot).
Well, great invis at level 4 vs blur+this (a 3 and a 2)
both result in a basic combat effect of someone else getting disadvantages applied to targetted attacks against them The invis also applied advantage on attacks made by and the built-in lack of location known when not revealing themselves.
offset to this is that the greater invisibility locks down the spellcaster's concentration slot. So the advantage for the target in their offense is weighed off against the lack of concentration for the caster. Also, greater invis require's the caster to make saves for damage using CON instead of the protected individual. Unless the caster has CON as a favored save, that can be a serious difference,
especially since they are not getting the defensive gains.
basically, while those elements may at times seem to offset, one of the bigger worries i would have with this approach is the global shift of opening up spells with a SELF designation to de facto all become 1 TARGET. it seems to me that many times in the rules spells with SELF are given to be "balanced" somewhat by that restriction on casting on other targets.
So this approach not only opens the action economy and concentration cans of works but also the "self"ish can of worms too.
I would view it as a riskier and even more indirect treatment to the issues some have with concentration. its "scope" is unnecessarily broad to deal with the issue and for me would open up more possibilities of unintended consequences than a more direct, more "individual review" kind of approach.
But, thats biased by how i design things, analyze and treat issues, so i am sure it would be appealing to some who have other ways of doing things.