Yes... But only, and ONLY, if they know how to sing it right. I hate it when some bands feel they can do the song justice, and FAIL miserably. If you can't do it, don't push it. There are other songs out there.
It's fine for me. The thing is most people will find them as a bunch of rip-offs. But yeah, they're just expressing themselves through music. it's like they're only making a "fanart" by using music as their medium. That's how I find it. And besides, they're making that much effort so why not support them XD
In the words of the judges on American Idol, "There are songs that are just untouchable"
For Japanese songs, I feel almost 100% the same way. I can accept the Japanese sounding weird when they pronounce English with their accents. I'll even accept songs that contain Engrish. For God sake people, how long has japan closed from the rest of the world? (point made)
But Foreign people trying to sing Japanese songs? I'll give the guys credit. But most of these cover bands rarely consider pronunciation and have exaggerating amounts of fandom for the japanese culture. Sometimes not even Japanese culture but just Anime. I can understand now why most Japanese consider foreigners as outsiders. To me it looks like bad flattery or smothering or maybe even brown nosing, what most of these cover bands are doing.